Screens are currently out of stock baecause a sub-supplyer stopped producing a needed part. Once a solution has been found the next batches will probably be sold out very quickly, but hopefully after a while things will normalize.
What do you mean by “screen reliability”?
A new battery was not announced yet, but for the FP1 they suddenly had a new battery with more capacity without any prior announcement - so: nobody knows.
The FP2 has a built in cover that keeps the phone save from most damage caused by falls from human hight. Just don’t put the phone into the same pocket as your keys unless you use a screen foil.