Panasonic Eneloop BK-3MCC (4th gen) - where I can find maximum discharge current?
I think you mean 6000mA discharge. I don't see an 8000mA discharge curve there. If the ambient temperature is 25C then yes, you should be able to pull at least 6000mA from it. 

I think that the safety factor would be highly dependent upon ambient temperature and how fast you're pulling the heat away from it. Otherwise, I've never heard of NiMH having issues with fast discharge current unlike lithium ion batteries.

I used to have a remote control plane that would suck the NiMH batteries dry in about 10 minutes so that would make them capable of at least 6C discharge. That was probably 10 years ago. I can't imagine batteries getting worse with time.

At 6A current draw, that's only 3C, so my guess would be that you have some room to play with. Anything beyond 6A should be experimentally tested as the datasheet doesn't show anything beyond that.