In-engine animations/transitions etc like the ones you described are encouraged! They're a part of code and therefore don't count towards the character limit
And for the second question, beeps can be used for voices! (and would be( as you described) taking the "slot" of a regular VA:
ONE VOICE ACTOR
Your entry's single voice actor...
- can be replaced by sound effects / beeps processed to act as voices (this does not count as the sound effect)
Regarding usage of voice beeps in lieu of voice acting: you may create different beeps per character as long as it remains consistent to that character.