I'm probably gonna get a lot of crap for this and I know it's not on the list, but I would suggest exploring the use of a Seneca II.
I've been instructing in them for over a thousand hours now, and I find them a very stable, forgiving platform that is still plenty capable.
Don't get me wrong, the MAP adjustment will make your hair gray in short order and MX can be a problem, but the low acquisition costs of a II might help make up for some of that.
I think that it flies a lot like a Seminole (note that I said "flies," not to including takeoff and landing) with more interior room and overall capability.
Some people don't like the Seneca for a primary trainer mainly because of the simple turbocharging system and the forward CG that'll require you and/or your student to jockey ballast around, but I've come around to liking them.
Like I said, I realize that it's not on your list, I just wanted to make sure that you weren't discounting what can be a pretty good trainer.