No. Они can be used with any gender. Examples:
Они́ актри́сы. - They are actresses. (актри́са is feminine gender)
Они́ актёры. - They are actors. (актёр is masculine gender)
Они́ я́блоки. - They are apples. (я́блоко is neuter gender)
Note: in the Russian language in the plural noun, gender cannot be determined.
Yes, "ы" or "и" for most cases. But sometimes stress changes:
слон - слоны
стон - стоны
(bold shows stress here). It seems there are no any rules, you just need to remember correct stress.
I have heard in many slides, "ы", pronounced as, "ee", like in, "meet". In this slide it is being pronounced, "eh", like in, "bet". What is the correct pronunciation of, "ы"? Does tge pronunciation change?
I'm a bit confused, how am I supposed to know that I should've picked the plural version of the word "Actor" Does the word Они change depending on if the next word is in plural or not?
This was from 3 months ago so you've probably already figured this out, but for those who are asking the same question, они means they, so any word that follows it would have to be plural. "They are actor" doesn't make much sense.