On 1-3, I am very much looking forward to learn the dark arts & sciences of crest and switching 🤓
And you're right of course, in an ideal situation where you're just switching sides on a crest a lift kit shouldn't make too much of a difference since the diffs clearance are likely to be your limiting factor.
Technically speaking though (the engineer in me apologizes) a lift kit does lift the whole chassis, not just the body, and with it up goes the engine, exhaust, transmission etc, in other words all that bolt to the chassis (hence why the COG moves substantially with any lift kit like you rightly mentioned before). And although the axles haven't moved, the approach, departure and break-over angles have increased because of the extra chassis clearance. So if you're a newbie like me and haven't done things "just right" the first attempt, that extra break over angle may bail you out that split second later, or if you decide to stay on the crest for longer and experience dips and bumps along the crest, that extra clearance in the middle will make things a little less sticky (which is what I was referring to).
Can't wait to make little crests with you guys this weekend and talk physics in the sand like our ancient ancestors! 😅