I wouldn't pass the source code to anyone before start. You should know why.
Source code will be available before launch (
excluding the PoW function).
The hashing part will only contain prototype functions.
You won't be able to do anything with it, except checking if you setup your compile environment correctly.
Anonymously, or "anonymously"?
Anonymously as in Bitcoin "anonymously"
So does this mean the primecoin gpu miner could be ported to this coin.
Theoretically yes, but it will be much harder than just copy paste.
If I understand correctly, you need to find prime numbers to work out prime gaps?
Yes