1. Will I give feedback on submissions before the deadline? Yes, if asked. If not asked, I may give feedback if I really like a submission except for one or two problems.
2. Is variant multiclassing allowed? Yes.
3. Retraining? I'm generally pretty ok about retraining, even for free, if the reason is good enough. For example, I would allow a sub-optimal, RP-focused initial build (say with aristocrat levels), which could then be RPed as learning and retrained for free over the first adventuring day or two.