The training books are actually not used at all in the new recipes. Crafting was revamped in 1.19 and streamlined the process so you don't have to gather a million materials or take a ton of steps to craft things. Guildmark-bought abilities for crafters I believe are going to become learnable as you level up.

As for what will happen to Guild Marks, it seems like the devs are heading into the "get rid of them" direction, and will implement a system to trade in guild marks for items, gear, company seals, and/or gil, but they are still deciding on the specifics.

Concerning leves: They don't exactly "reset" now. What happens is every 12 hours you get 4 slots that you can use towards any combination of Battle, Crafting, and Gathering leves. You can stockpile up to 99 slots. The leves at the counter replenish themselves when you get new slots (so 12 hours), or if you complete or fail a leve.

Mooglebox is the best item/crafting database I've come across so far. Yg took months to update with the new recipes and in that time Mooglebox updated all their recipes, added new search methods, and yes, nearly every recipe there has the correct level since the owner had a campaign asking people to input their xp from synths which were used to calculate the levels.