Going to need a rear wheel,
For a 29er, should be peanuts. New or second hand.
Rear Mech
Again, if 10 speed, should be able to get a new or very good deore or slx for a tenner.
Dropout screws
Droput screws must be non-one off? Take it to a DIY shop. Or ask On One?
Front Brake
Chain reaction were chucking our M395 for £20. Bike discount.de about the same.
I’d replace what you have. And if nothing else, you will sell that bike for more than the cost of fitting those.