I doubt this would be a problem. In fact, it's not really all that unconventional. While there are ostensibly fewer DRPGs that use that kind of system than those that use more of a jrpg style turn based one, it's a pretty natural fit and is hardly unheard of. There are also some hybrids around. Legend of Grimrock uses a similar movement model, but, instead of simultaneous moves, has it happen in real time.
A simultaneous turn system along those lines is also not the worst to code, though pathfinding and AI are always kind of a pain, and this framework can end up being more structurally complicated. I made a prototype of this kind a while back, and I'm hardly the best coder. So if I can do it, it's probably quite achievable across the board. That said, if you want to implement it from scratch in under 8 days, along with doing everything else, it'll certainly be a challenge.
But then, I guess that's kind of the point.