G19, not sure on the blade.
SHTF: If you're really talking true SHTF, it'll be dirty, loud, chaotic, desperate, resupply may be neccessary, concealment will be necessary, bartering may be necessary, weapon maintenance will be the last thing on your mind.
Gun: Glock. Ubiquitous. Interchangeable parts. Runs dirty. Runs broken. One time found Id been shooting off and on for months with one of the lug pins snapped clean in two. Wouldnt have even known it, til I broke it down.
Caliber: I love 45. Love it. But 9 mm is the most available, and lightest of the 3 main calibers. Its easiest to acquire AND easiest to sell/trade, should that be necessary. Easiest for the wife to use too.
Answer: G19. I realize there are competing polymer, striker-fired brands that would be as durable, but they aren't ubiquitous.