The pump fuel hose on top leading to the filters is slowly leaking at what appears to be the threaded female fitting where the hose attaches into the pump body. Is it okay to try Teflon tape?
No. For the same reason that teflon tape is not allowed for gas piping in most building codes- teflon particles can plug tiny orifices, you shouldn't use it for fuel systems.
Agree with everyone above. No tape. I use permatex aviation sealer. If I don't have any on the boat I might use transmission gasket maker. Run a small bead around the threads and stay away from the first 2 or 3 threads.