Battery powered is okey.
Being limited to "what's in stock" could be like going down a dead end road. Nevertheless, 433 ought to work.
Ultra sonics uses more power than f ex a microswitch especially 433. Not the best.
Concept.. What about time between battery changes/charging?
Use an Arduino using low power, has a sleep mode. However the ultrasonic will consume energy....
Current consumption depends on the consumers used. Your choice how often You like to change/charge the battery.
Not knowing everything about 433 I would say it's okey.