Regarding Extra Roster Spaces

[Boco]

So I've been thinking a lot about the topic of roster size recently. It's a real downer to not be able to have space for monster breeding or hiring/inviting extra units near the end of the game without getting rid of a unique character (I consider Ladd, Alicia, and Lavian integral to the team).

So, rather than using the Roster Hack to extend the party roster size from 16 (I read that this hack can't handle accepting monsters into the extra spaces), am I correct in thinking that I can use Xifanie's "Guests In Randoms and Unit Restrictions" spreadsheet while making Boco, Worker 8, and Byblos all guests (and controllable)? This would make them immune to crystallization, though.

If they took up guest slots 17, 18, and 19, then it should give you an extra 3 spaces to work with for monster breeding or hiring/inviting other people? Byblos is the last one you get, and if you only use those three as guests, then you always have room for at least one guest you might find in a random battle, and I'm pretty sure any situation giving you two guests happens before you get Byblos.

At the moment, this is only pure speculation on my part; I have not tested anything yet. I'm still very far away from completing my personal patch. Anyone have any insight on this?