what happens to my donation if the project fails to get funded?
It looks unlikely at this point that the project will not be fully funded. I plan to make a donation soon as well.
There doesn't seem to be a deadline for the time to receive donation funds, so I imagine Anonimal would continue working as they do now and eventually it would become fully funded.
I think if the project is abandoned by the developer, then the donated funds are reappropriated at the discretion of the core team. Probably they would remain set aside for work on Kovri. This happened for example with Trezor (roosmaa started working but quit, then NoodleDoodle took up the project and got the funds, hyc also got the solo miner working after someone else dropped out and got funds, etc).