Keeb IO Build: Questions and tips?

I was thinking about buying a Keebio Sinc keyboard despite never owning or making a mechanical keyboard. https://keeb.io/collections/sinc

There are some tangible benefits of this keyboard that I really want -- specifically a split mechanical keyboard with QMK support (my current keyboard has a crappy driver situation, I would like to avoid that by using a QMK compliant keyboard) and the price is arguably pretty good for a split keyboard. I haven't found one that suits my needs for a cheaper price -- I don't necessarily need hot swap-able, but I imagine it will eventually help in the case where an individual key stops responding. If anyone knows of another deal that's less hassle or better value, let me know.

Anyway, basically I know very little about building my own mechanical keyboard or just owning a proper mechanical keyboard. But I figured that if I wanted to buy a split keyboard, which are already expensive, I may as well delve into the world of mechanicals at the same time. I know there are a few well-advertised gotcha's around the keebio builds such as needing to buy a set of keycaps if I build myself and appropriately ordering the right number of stabalizers.

However, I have more questions that aren't as easily answered searching so I thought I'd ask people who know a lot more about this than I do.

1. How do I know exactly how many stabalizers I need? Additionally, how do I make sure that I buy the "right" set of keycaps for the keyboard I'm making (do I look up "ANSI keycaps, ISO keycaps" or is there some other trick to make sure I buy the right "set" of keycaps?)

2. If I build my own, what other gotcha's do you think I should know that aren't advertised well on site?

3. I know that Keeb.io offers prebuilt versions, but how do you feel about the cost difference and shipping quality? Obviously it's much easier to ship disassembled than assembled,.

4. Is it a smart idea to build my own before having owned or maintained a mechanical keyboard? Despite the much higher cost, is it worth it to purchase a preassembled keyboard?

5. How do you feel about Kailh Jades vs Durock Shrimps vs Durock Dolphins? Those seem like the 3 most likely switches for me to try and most likely for me to like of the options provided on the site.