Regarding how the developers get the ICO fund, I would suggest a weekly payment based on the quality of update and github submission.
Meanwhile, if the release of the BitBay wallet is nothing but a simple clone of Blackcoin and BlackHalo, I don't think it could worth more than 10 BTC.
Of course, more BTC could be reimburshed for reasonable advertising cost, etc.
To make it simple, no work no pay. If the team runs away, the rest of the fund could be returned to the investors or used to hire another team.
If all the fund is given to this team who just produces a simple clone of Blackcoin and BlackHalo, I believe the team might have a strong motivation to take the money and run away. It is not difficult to produce a clone of Blackcoin and BlackHalo (which just worth 10 BTC), but it is really difficult to finish the rest of the roadmap (2990 BTC work).