So my son is going to his high school formal they don’t wear tuxedos but do wear dress slacks vests and bow ties he is wearing all gray with a coral bow tie to match girls dress what looks better shirt a little darker gray or a little lighter gray vest and slacks are the exact same gray
That’s good that the vest and trousers are the same color – it gives the appearance of a suit and the same advantages of projecting an image of taller, slimmer!
The shirt can be white but gray is fine just make sure it’s a different shade. Lighter would be better.
If there is dining at this function, this table manners article may be useful: