Upvote:3
You would indeed two VoAs each, and that would be fine as far as Immigration is concerned. As long as you leave within the allowed time, Thai Immigration won't care.
However, why bother? Just do all your Thailand visits on your first VoA, then fly to Cambodia and back: you can transfer in BKK on your way back home, without needing a second VoA, if you use one of the airlines that fly to Cambodia from BKK (assuming your flight home is from BKK too, of course, since you say you're from the EU, and there's no flight from DMK to the EU).
You'll save quite a bit of money, and time, applying for only one VoA each... As you'll see, the VoA facility in BKK can be a fine circus if you arrive around the same time as a flight from India or China...