Originally Posted by sch

Can't easily google up a pix of the bike, but I tend to agree with the poster
on your other forum where you posted the same question. With two
major systems malfunctioning on a Walmart grade bike, it is scrap metal.
Even if you could find parts, likely you could get a new bike from WallyWorld
for the same price or less when you throw in R&R costs. Look around for
a less trashed junker. If there is a big college/university around they may
have a few dozen leftovers abandoned on campus in the lost and found.
The shift problem may be trivial or equally fundamental to your stripped
crank problem. In the absence of expert opinion try something else and
leave this one on the curb somewhere.