1. Yes. Map a button to "Toggle thrust reverse". This will bring the power lever back to the beta mode and you can taxi. Bringing it back further will bring it into reverse.
2. If navdata is new, it can sometimes take a few weeks or a few months to make it into the next navdata file. However, in saying that, make sure your navdata is up to date.
3. You can literally download the actual TBM operations manual and use that. There are links in the documentation we have included. Here's one of them with the performance data included.
https://www.tbm.aero/wp-content/uploads/2016/03/PIM__900_AN__E0R2.pdf