1. Actually, when you send your proposal on the GSoC site, it's only visible to the organization administrators. Then, there is some time left (until March, 27th) to give you some private feedback and let you improve your proposal if needed. Regarding the fact that there are some ideas without any mentor assigned, this is not a problem. We aren't sure yet who can mentor students but your proposal will be handled by someone proficient in the concerning area.
2. Yeah, sure !
3. As per the GSoC rules:
- Each student may submit up to 3 proposals to the program.
- They can
submit multiple proposals to the same organization for different
projects if they wish.
Hope this answers your questions !