1)
Yes, and your yields might even go higher, as the nitroethanes, usually are easier to reduce than nitropropanes.
2)
Yes and yes! You can most certanly use potassium formate of even formic acid. AFAIK KCOOH is an even better hydrogen donor than ammonium formate, which is only good in this case.
3)
The temperature should be kept low aswell! Be carefull if you chose to use formic acid, as the reaction is vile.
Regards
Bandil