basically he is.... Kurama is a male fox

yeah, but doesnt mean in game he is

I'd say the primary decision should be whether you can make use of her barrier. Because if not, she's not all that good as far as damage goes. The poison and igniton doesn't work, the poison still gets animated which wastes time, her mystery is relatively slow being animated and is weak for its cost (granted, not weak in and of itself, so perfectly fine for turn 4 when you have chakra to burn, but turn 2 is a clutch. A 60 chakra AoE might do more than a 20 single target, but if you can cast the latter twice while the former only once... well...). And she certainly don't come with a usable chase in fox.

So it depends on if you c*e her barrier. I did make an attempt with GNW tenten and kisame once, it worked decent. I had wind main the chase-chakra talent, positioned in spot 1 while kisame in spot 2. This allows very high powered kisame strike as well as provide sufficient chakra to turn 1 tenten, turn 2 kisame-mei, turn 3 tenten and turn 4 kisame-mei (tenten/mei casting AFTER kisame had his normal attack ofc, to enjoy the boosted attack power from chakra) and it worked decent. It was far weaker than my wind team but... I'm wind main.... maybe fire/water can find a better team with the barrier.

In any case, the barrier is what you are REALLY looking at as far as Mei goes, don't worry too much about the other stuff. I'm sure GNW tenten surpass her in every other department, for example.