Alpha hair closely resembles Sims 3 hair if that helps. You'll have to look at some and decide what works best for you. If you want some super cute, short ponytails, Nightcrawler's Biscuit Hair is my favorite and I'd use it if I weren't into Maxis Match (MM is the term for clay hair and other CC which follows EA's style.) There are also some Simmers who create a Maxis Mix (like a mix of Maxis Match and Alpha) which has more strands and other details to combine the two styles but you may not like it as much. Alpha hairstyles tend to be more realistic: Nightcrawler and WingSims are the ones I know of and they're extremely popular, but many people create alpha. Yes, but you need a lot of Alpha Custom Content (CC.) Look for that term and you'll find a ton of options a lot can be found on TheSimsResource (TSR) but you can find them elsewhere, such as Tumbler and Patreon.