Isn't it wonderful to have too much? I know the pineapple guavas can survive and even thrive here in the Seattle area but I don't know anyone who actually has them. I really like mixing in "productive" plants into the landscape and have researched a lot of options, it's amazing what can be grown here.
Most everything I'd make would be against my low carb guidelines, you might try a search on "feijoa" recipes. You can do baked goods or make it into a paste or all sorts of things.
I think I'd probably process the pulp into ice cubes and add them into smoothies or maybe a holiday punch?? -- not that I can have many of them.