If I only take one set up with me walking the bank and all I have spooled up is fluorocarbon but decide I want to throw a popr could I tie on a mono leader and work the popr effectively considering floro sinks? I feel like this is a dumb question but I been really wondering about this?

I dont know about 100% effectively, but it could work. The problem is that if you make a long cast and have a lot of fluoro in the water, it will make that mono sink, thus canceling out the effect you are looking for. You'd be better off just keeping your rod tip at 12 o clock and working a popper that way, keeping most of your line out of the water. Having 2 knots is increasing your odds at something failing and losing a fish. If you dont NEED a second knot, don't tie one. Just my 2 cents.

Just use fly line dressing about 3' to 5' of line in front of the surface lure to float the FC line.

Tom