Welcome,
My advice keep the Mosin in it's factory configuration for the simple fact that old military surplus seems to appreciate rather nicely over time.
I have acquired several surplus rifles and handguns over the decades and the value just keeps going up on all of them unlike some of my more modern toys.
I would also opt for a " better" budget optic than the Banner which is a lower end Bushnell. This comes from the frustration of having optics fail over the years.
I'm sure their are plenty of brains to pick about things firearms related around here so enjoy and it's good to have you.
BHJ