>2: it makes sense to me because if we can flip/rotates ia particles spin, why don’t we flip an antimatter particle?

"Spin" in particle physics isn't actually the particle spinning. Its just a name for a measure of angular momentum.

>why don’t we flip an antimatter particle?

Not sure what you mean by "flip". If you mean measure the spin, we can. A positron is an antimatter particle, and we can measure their spin.

>you’re probably not fun at parties

Why bother asking the question if you don't want / can't deal with a serious answer?