Hi Sarah, I'll try to give some answers here :
SarahBeth said:
So if I am just, say, showing one film should it still be افلام or فيلم ? Does the plural indicate that there will be more films or what?
Yes, the plural indicates more than one film, so if there will be only one just use فيلم
Also, what purpose would عندي in addition to the اقيم serve? (That said, I can't figure out exactly what اقيم means? It exists/takes place/happens [at me] )
Does it clarify or refer back to the fact that I am hosting it and should I still use it if I say في بيتي at the end of the sentence?
عندى means "at my place", so it's important -in the Arabic sentence- to determine WHERE you'll be hosting the night. You can either say عندى or فى بيتى or even عندى فى البيت, they both give the same sense. I don't think you can skip them both, better choose one, even if it's implicitly understood that the soiree/night will be at your place.
Uqiim أقيم means : organise, so it's something like : I'll organise a soiree at my pleace for Arabic movies.
Sorry for all my stupid questions.
Also, I like soiree much better. It sounds oh so elegant.
Your questions are not stupid at all

I also like soiree better

so in Arabic you can say : أمسية، سهرة، ليلة they all give almost the same meaning. In Egypt we mostly say sahra سهرة when we're inviting people to our home.
So you can say : سوف أقيم عندى سهرة لمشاهدة بعض الأفلام العربية
or : أدعوكم لمشاهدة بعض (أحد) الأفلام العربية
If you want the colloquial form let me know.