New 5th wheel vent fan install

I've just replaced my 5th wheel with a 2021 Cougar 354fls. Since it has a front living and rear bed/bath the roof height in the bathroom means I can't reach the vent to open. I'm replacing with a Maxxfan with the remote.

So here's my problems/questions.

First, my previous 5th wheel had an EDPM roof and I'm not sure what keystone is using on this model. Both sides of the membrane are white and from what I understand EDPM has a dark backside and TPO is white on both sides. Here's a photo of the membrane:
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Second, whatever sealant Keystone used at the factory is very tough and appears welded to the membrane. It doesn't appear to be dicor, perhaps silicone? It is very solid, somewhat pliable but extremely difficult to remove to prep the surface and I'm concerned about puncturing the membrane. I've tried mineral spirits with no success although I haven't let it set for very long.
Here's a photo with the vent removed and the sealant that needs to be removed.


Any suggestions or comments are welcomed.

Thanks
Joe