Note that android switched from gcc to llvm a while ago, so I don’t think that a gcc based toolchain will be very useful. RISC-V support was added to FSF GCC as of gcc-7.1. You can’t find older gcc versions unless you use non-upstream sources that support older RISC-V architecture versions, which are unlikely to be useful, and unlikely to be stable.
On top of that, there is also a group working on the rest of an aosp port. I think it is mostly the same people as the v8 port.
If you want to chat with these folks, I would recommend the RISC-V International sw-dev mailing list. Though it looks like you already posted there, so I’m not sure why you are asking here. The SiFive forums are mostly for discsussing SiFive products, and SiFive is not directly involved in any of this work at this time.