Well, the fenders worked. We took it out yesterday and I had a little rubbing on the front right, but I can trim that down.
We ended up with a loose chain due to the previous owner aligning the chain by loosening the jackshaft rather than lining it up by moving the lower sprocket. The chain caught and broke, we fixed it but I think it must have damaged the key in the upper sproket because it eventually started spinning on the shaft.
I'll need a new key (or sprocket if the key is built into it) and maybe a new shaft if they've been running it loose for a while. I might as well throw on new bearings when it's apart.
I'll check the chain out too. It looks too wide, like they put on a bigger chain at some point. Luckily most of the parts are generic enough that I've been able to locate them. I'll take it apart and see what needs work before ordering parts.