Ehno doesn't actually know about Solomon yet...he's been away for the past couple of weeks, so that's going to be rather interesting for him. He'll be a bit O.o, but honestly I'm not entirely sure how he'll react. Kind of depends on how Franklin explains it. But definitely interesting.
Trick is one of the people he'll probably need to meet-looking forward to that. Ehno will likely be a little overwhelmed as he's a pretty subdued personality.
Harold might have been someone Ehno had contact with aside from Asmo, if he was in trouble enough that anyone would hire a PI to look into him for some reason.