Shining force cd level query

I'm making my way through Shining Force CD at the moment and am most of the way through the first game (I've just defeated Dantom), and I was a bit mystified as to how characters' levels carry over between chapters. I've spent many hours power levelling the characters (all promoted at Level 20, all now around Level 9 promoted except Mayfair, who is Level 16 - gotta love Aura) and I'm paying particular attention to the characters who are forced into the Museum Party (don't tell me if the ending's worth it or not, even if it isn't, defeating the Museum probably makes for interesting bragging rights to a select few) - namely Nick, Ruce, Shade, Wendy, and Claude.

My question is this: I know that Claude and Nick are also party members in the second chapter, and that their levels upon joining the party do not necessarily correspond to their levels at the end of the first chapter (I've already levelled Claude to beyond the level at which I gather he joins Deanna's party). In the third chapter, when everyone who joined the party in either chapter is on hand to take on Dava and Co., will Nick and Claude's levels be the same as they were in the first chapter or the second?

An extension of the same question: would I be right in guessing that the levels of the characters in the Museum Party will be the same as they were at the end of the third chapter, or will they be reset to their levels at the end of the chapters in which they joined the party?

I'm hesitant to press on to the battle against Woldol until I know whose levels will disappear between books (presumably Ruce, Wendy, and Shade will keep their levels throughout; I'm mostly wondering about Nick and Claude).