That is a ton of questions... if you're going to ask many questions, you should label them or answering them becomes a real chore. People are going to skip questions.
The short answer is... just play a lot.For Advents, just run Ultimates? If you can't do Ultimates, do what you can to power up.
If you can spend 16 hours of AP per day and the event lasts 7 days, then it's 145 Gold tokens-ish from AP alone. The SSR Eidolon costs 150 and the weapon costs 125. About half of those is from the last purchase, so a single Plat chest drop cuts the amount of farm down from 275 to 215-225. That doesn't happen every time, though.
You need to pot to make up for the difference. Half-pots are a valuable resource, but thankfully they're relatively plentiful.What? How? When I picked up KH it was on day3 of Crom's Crotch, and I got 60+60 in the 4-5 days left in the event. On a brand new account. So... how? Just... play more? You just need to hit the boss once to get your Soul and then can come back to KH after 40-80 minutes to do it again...Raid events feed you in SSR books, SR books you get a few here and there. I hear getting SR books will now be harder, as they might be removed from Raid Gacha Tickets... haven't confirmed it though. We'll see next week.
Not all that many SR Hime need to be LMB'd though, quite a few have a terrible second skill.
And, the only people who have a huge stable of SSR Himes are people who pay. And for them, SSR books are a huge problem. For everyone else who plays the game actively are probably just outright flooded in excess SSR books.I don't think you should ever spend weapon materials on Hime levels, what a waste. Just play the game. Ultimate Advents are a really source of exp, Raids are decent, 25 AP dailies are okay (and amazing on Sundays).
Advents are the best times to level up Hime especially at the point where you're potting to make up for the lacking Gold tokens. Like 50 runs for 130 Gold tokens is like 65k exp or so. That's enough to go from level 1 to 50ish?
Sooo...
tl;dr; do the best that you can if you can't run Ultimates yet, and once you can, it's just a matter of how much time you can put into the game. And "time" mostly means "spend your AP regen" more than anything, as you don't really need to get both SSRs from all events if you don't want to.