Is drawing a friendly face or picture on my N95 masks safe?

Of course I can't say for certain, but there are N95 masks that are dyed and have designs on them. That said, those masks are likely tested with their design.

Just my 2 cents, but I'd probably say if you draw on a small portion of the mask, like whiskers etc, it would be fine. The mask would still filter and I doubt the dye from a marker would change its effectiveness. The worst thing I can imagine is it possibly causing slightly less airflow in the parts that are colored, but I even doubt that unless it was just overloaded.

I'd be interested in other peoples opinion too, kinda curious myself.

n95 won't protect you regardless, the virus is smaller than the mask's effective size range.