I think Wyshnalyrr is a must but A&H aren't necessarily. I mostly suggested that since it makes the most out of the models you have listed there and...
But it does almost nothing for Galleon since he's so easy to hit and if I'm hiding Ashlynn behind Galleon I'm limiting the enemy models I'm catching...
The thing that gets me about Midas is that he feeds off his beasts, but doesn't do anything to really improve them. He doesn't make them faster, and...
It's not so much that it's bad on Galleon as it's better on most other things. 4" extra movement is nice but you don't get any real meaningful boost...
I think they're a great toolbox unit for Mercs. A damage buff, and access to magic weapons go a long way for Mercs. POW 12 handcannons are never bad...