You had a few preliminary questions before your dream, so I'll try to answer most of them.

o  In many of your dreams, you mentioned different guys that you know or have known.  I believe that there is a very good chance that some of them (perhaps all) are symbols of your animus.

Using the theories of Carl Jung, the animus is an archetype from the collective unconscious.  The animus is always male and is only found in the dreams (and psyche) of women.  During the course of many dreams, the animus can potentially go through four stages of development.

1.   Stage 1 -- The animus is the physical man.  At his best, he is the muscular hero who saves the maiden in distress.  At his worst, he is a materialistic brute who is only interested in his own self-gratification.
2.   Stage 2 -- At this stage, the animus is either the romantic lover or the man of action.
3.   Stage 3 -- At the third stage, he is a man with a message.  Common symbols for the animus at this stage would be a politician, a preacher or a professor.
4.   Stage 4 -- At the fourth and final stage, the animus becomes a spiritual guide for the dreamer.  Although he is a guide, he may not always be a religious figure.  The animus could appear as a wide range of different men.  This would include (but not limited to) the Dalia Lama or Carl Jung.  And, I believe that the animus at this stage will sometimes show himself as mythological or pagan deity.  Examples would be Odin or Loki who would most commonly show themselves in the dreams of women with northern European ancestry.

If they are symbols of the animus, then the different guys probably represent changes in the animus, but not necessarily different stages of the animus.  Trying to determine the stage can be a little tricky and is not always obvious.

o  You also asked about the meaning of a dream where your ex-husband married a Russian woman.  If we continue with the Jungian approach, then your dream ex and his wife are a symbol of syzygy.  This is the joining of opposites and is almost always a good sign in a dream.   Such a dream couple is sometimes called the Sacred Marriage, the Divine Union or the Royal Couple (among other names).  This interpretation if supported by this new wife being Russian.  Russia is sometimes called the Motherland or Mother Russia, which emphasizes her feminine and helpful nature.  But, since I believe that most dream people are symbols from the unconscious, then both of them would be helpful parts of your unconscious. 

o  As for dreaming about your dead parents, it is difficult to be sure, but it may be that visits from them or dreams about them are, in some way, actually about your parents.

o  As for school dreams, they can be very pleasant and gratifying; however, it seems that many of our school dreams are frustrating and stressful.  These dreams could have something to do with your being in school -- but I doubt it. 

In most of our school dreams, I believe that the school that we are attending is the one that we all attend.  It is the school of life.  In this school, we do not get good grades by studying hard.  Instead, we do well in this school as we grow and develop spiritually and psychologically. 

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Now for your dream --

Going out to a party, celebration or a "fancy event" is usually a good sign in a dream.  You and your ex-boyfriend are in a theater (apparently to see a play or a movie).  The play (or whatever it is) is probably about you -- your life or situation.       

You are wearing Heather Locklear's long, orange gown.  I?m not sure about the significance of HL.  It may be that she is in the dream to show the importance of the event.  Or, (probably more likely) she may be a symbol of your shadow or some other archetype from the collective unconscious.

The shadow is always the same sex as the dreamer and is, in some way, the opposite of the dreamer.  There are, in general, two types of shadows: one negative and one positive.  The more common negative shadow has those negative traits that a person wants to hide from him or her self and from others.   The more positive shadow has those positive traits that are hidden within the dreamer.  As a part of our psychological growth, the positive shadow will, hopefully, become incorporated into the consciousness.  Thus, those hidden, positive traits would no longer be hidden.

There are other possible archetypes for HL other than the shadow.  She might be the Great Mother http://www.mythsdreamssymbols.com/mana.html , one half of the Royal Couple or some other archetype.  But, the shadow is one of the most common archetypes.

You wrote that the gown was orange.  I believe that colors in our dreams are usually meaningful.  And, whenever feasible, I usually interpret colors according to the colors of the seven primary chakras.  The color orange is associated with the second chakra.  The primary function of the second chakra has to do with reproduction and sexuality.  http://www.multidimensions.com/Unconscious/uncon_emotions_2chakra.html

You got a stain on the gown while being a bartender.  Being a bartender means that you were preparing and possibly serving alcoholic drinks.  In real life, drinking cocktails, martinis and such can, to some people, have a negative connotation.  But, our dreams are not real life.  In our dreams, being drunk on liquor is a symbol of being spiritually drunk or being spiritually intoxicated.  Thus, being a bartender means that you are, in someway, increasing the spiritually of others.

I'm not too sure about the meaning of the stain.  But, I believe that it is positive.  It sounds like your ability to intoxicate others (in a spiritual sense) may have some kind of positive effect on you.  However, as you wrote, the dress is one that you borrowed from HL.  Thus, those things that are symbolic of the dress may be what you are getting from your shadow.   

You are next wearing a gown that is light turquoise blue.  In general, blue is associated with the fifth chakra at the throat.  Thus, this dress may have something to do with your communication skills, which you seem to be getting from your shadow.  The fifth chakra symbolism is supported by your dream -- as you wrote, the gown was "covering my chest up to my neck...."

A little aside --
In most of the dreams that I look at, one event in the dream often "causes" the next.  This is what happens next.  We see this when you went from the orange dress to the turquoise dress.  We also see this in the next part of the dream. 

In this part of the dream, you are in college, which means that you are continuing your education in this dream school. 

You are looking for a large, clean bathroom.  In real life, a bathroom is used for elimination and cleaning.  It has a similar function in our dreams where it symbolizes the elimination of problems and such that hinder spiritual/psychological development.

You saw some dirty clothes and tossed them to your right.  There was also an older man.  He might be a symbol of your animus.  The right side is symbolic of the masculine and consciousness.  Thus, there may be problems with your relationship with your animus.

As the dream nears its end, you have completed your elimination.  There is an issue about your stool not being flushed quickly enough.  The implication is that your spiritual/psychological education is hampered by the problems that you are having with the elimination of some problems (which probably have to do with the animus).

As for the Russian woman, I wrote about her earlier in this post --
You also asked about the meaning of a dream where your ex-husband married a Russian woman.  If we continue with the Jungian approach, then your dream ex and his wife are a symbol of syzygy.  This is the joining of opposites and is almost always a good sign in a dream.   Such a dream couple is sometimes called the Sacred Marriage, the Divine Union or the Royal Couple (among other names).  This interpretation if supported by this new wife being Russian.  Russia is sometimes called the Motherland or Mother Russia, which emphasizes her feminine and helpful nature.  But, since I believe that most dream people are symbols from the unconscious, then both of them would be helpful parts of your unconscious. 

Hope that this helps and is not too confusing.