If I really had to live that situation, One fly only, I would tie a catskill type dry fly with ribbed rabbit dubbing, a wood duck or mallard flank wing, grizzly hackle and a mallard flank tail. I'd tie it on a 1x long hook. That fly, like McAwful's grhe could be modified as needed.
spinner: trim the wing, top and bottom hackles
nymph: pick the dubbing to make it bushier, and trim the hackle and wing
caddis larva: trim the hackle and wing completly off
etc., etc