I’ll go through your suggestions and give my feedback:

Factions will be fore players and NPCs. You can set factions up to be allies, neutral, or enemies (I might add a few other statuses, I’m not sure), and you can be apart of multiple factions.

There’s already a tab to view who’s in your party. I might make some options for it to stay on the screen, but there’s no real plans to.

I’m sure I can add an option for some spells to target map tiles.

I don’t plan on adding a title system, but you can probably use the faction system for titles.

I don’t plan to add boss NPCs, but I might add an option for an NPC spawn to send a message.

I don’t have a reason not to add emails/saved PMs, but I’m not sure if I will.

I’ll be adding an enchantment system for items, and that will work with the crafting system (enchantments use spells which can act as additional damage).

I don’t have any plans to change the music system (except for not restarting the song when changing to another map with the same song).

You can do that with Events (which are already in the engine).

I’m thinking about redoing the whole guild system, but I’m not sure yet.

There should be a quest list gui already if that’s what you’re asking?