Hi Wayne,
Regarding your question 1, have you checked the previous posts in this forum? Lately people have asked a lot of questions (including myself) about the problem of finding the mode. Here are two links:
[Mode check plots look ok, but Hessian is still negative)
Also, have you tried running different mode finders, via the mode_file=your_mode_file option? Sometimes it can take a while and running one optimiser is sometimes not enough.
Best
Rob