It’s fine as long as you don’t plan on using your DJI warranty while the drone is still covered.
As for the third party batteries you're considering, it's hard to say how they'll perform compared to DJI's. I wouldn't assume all batteries from...
All good to do, but I would make it simpler, I would also put the phone number on the outside, where it is easily accessed. A finder, like a little old lady might not know how to take out the battery or know anything about a MicroSD Card…
A...