Some at the PGL guild will direct you further.

MNK is, for almost all intents and purposes, an augment to pugilist rather than a new class. You will use the same weapon, continue to earn pugilist skills (monk skills are obtained via quests every 5 levels). Anything pugilist can do, monk can do as well save for one exception: pugilist class quests can only be done by pugilist, but since you must beat them all to acquire monk it's a moot point except for legacy players who unlocked it in 1.0.

And yes, you will have pugilist, monk, and lancer skills all usable on the hotbar. There will also be one more class you can use skills from, but no others. In addition, you get half as many cross-class slots. A level 50 PGL and MNK get the same total skills, but PGL gets 10 cross-class skills while MNK gets 5 cross-class and 5 job skills.