Who will do the maintanance of the GUI after launch? This will be a continuous for future.
Have you thought to have a full time dev for UI, instead of contractors here and there.
Up to the community. IOTA is for IoT aka machine-2-machine payments primarily, I don't see a lot of UI updates being necessary in that regard. However of course IOTA might also end up being used for other more human transactions, but again that's up to the community.