Most likely were all relevant infos regarding wheel exchange already posted…crisscross at he forum…so it’s sometimes not that easy to find the desired - questions are always welcome 
There are a few traps to watch on the way to new wheels, to name a few:
- The front rotor has to be centered manually while the wheel is laying flat.
- Freewheels are generally hard to umount, even if new, and there is a special (cheap) tool required.
- Highly recommended is a hook key to release/adjust belt tension.
- There’s a high risk to overtighten the rear wheel bolt.
- Brake pads must be checked/adjusted after wheel change.
Regarding mirror;
Safety is there any…mirrors
nothing to add here from my side unfortunately,
except this system from which I’ve heard recently in private from another Strida fellow
