I couldn’t find the extreme cafe in Gambela, and I was looking for it in any place near and far the spot you indicated it on the map. The same with galaxy restaurant (and I was staying in 43rd hotel!).
Concerning the transport situation: I went from Gambela to Aira with a lot of dust on me but not a serious transport problem – it’s true that Gambela to Dembidolo is tricky, but the morning I left there was a big local bus (again, no minibusses! wouldn’t make sense if its just once daily) and two trucks leaving for dembidolo – but because of the difficulties you indicated in the guide, I was asking around alot the night before – which wouldn’t have been possible without amharic (which I speak quite fluent meanwhile). the busses leave as early as 4 am at the NOC gas station (at least they say so! still I had to wait half an hour untill someone appeared at the gas station, and another half an hour untill the trucks were ready) but will pass the busstation for dembidolo (which is not the central busstation but close to the market on the way to dembidolo! the spot was indicated to me by someone the day before) where there would be a bus waiting from 5 am on and takeoff at probably 6 am (sometimes later, sometimes earlier). The drive to dembidolo only takes 3 hours, from there to aira it was more of an issue… (lots of stops)