Invite [Character Name] titles: How to obtain them?

[Ryoki]

I tried repeatedly inviting three people and uninviting them, but I have yet to get the titles for it.... do you have to finish a mission/field for it to count as one "invite"? or simply need to access the field and return?

[Hatrix]

I got a few but I think you actually have to complete the whole field or quest.

[Macman]

You have to finish a run though a field/quest with them.
I have all but Reve's.