@Crimson Raven Hey, we've all been new at some point. This is my first try at actually GMing a tabletop (tried small campaigns with my siblings before, but not sure those count), so we're both experiencing a first here lol
Not a bad question. For the moment, none of those classes are available. Vanguard, when included, will not be as it was in Awakening. It began as a Tier 3 promotion for Hero back in Radiant Dawn, so it will instead be one of the "Hidden Promotions", being accessible from the Mercenary when a special item is used. This will be the same for the Dark Magic-wielding fliers (well, promoting from different classes, but the mechanic is the same). As for the others, no plans have been made yet, though they are possibilities in future updates. I do have Butler/Maid in the works, though they are not visible on the Spreadsheet at present, and the same goes for Manakete and other Laguz-related classes.
A list of available Personal Skills are included in the System. Only two of these are restricted on what kind of unit can use them (one for foot units and one for mounted/flying). Aside from that, there may be certain Skills I deem too powerful for the early game. Aggressor is one such example. Others will be brought up when the issue arises.
For Class Skills, be sure to check the System sheet for all of those. The character will learn those which are appropriate at creation. Otherwise, no Mastery Skills right now, and for Unique Skills, PM me if you would like to create one. The only "Unique Skills" which are allowed to be duplicated across multiple characters are those I create for the Outrealm Demons.
Lastly, welcome to Fire Emblem: Dimensions! We hope you enjoy your stay. :)