It will be interesting how this team will work out indeed. I don't see any problem with Tommi testing the car at the moment, because even though he basically hasn't driven any WRC for over a decade now, he's not an idiot, and he can tell if something is working or not. Remembering how the Hyundai looked in 2013 and comparing it to the Yaris, I say they'll be at least decent (but I'm not an expert on this either).
As far as the team structure goes, I think they're still figuring things out how that should be working. Give them time, and if they flop they flop, but hopefully they won't.