I don't know what possessed you to pick that one, but you can get far cheaper Cadet heaters. A heater of that size should cost $50-100. All of them are 100% efficient - an electric heater that is less than 100% efficient is impossible.
That "cool feature" is actually 100% useless to the consumer. You know your voltage so you can buy a much simpler single-voltage heater that has fewer failure points. That "feature" is only cool to contractors, who get to stock only 1 heater and simply pass the feature cost on to the customer.
So I think I just saved you about $400 :) Now we can fund the circuit(s) needed to do the job.
This unit is 8.3 amps @ 120V. Because it is a heater, we must provision for 125% of that ampacity, so we must provision at 10.4 amps per heater. Welcome to 120V heating.
Not enough capacity on the circuits.
It must be hardwired. When a hardwired load is more than 50% of circuit ampacity, that circuit cannot have any receptacles. Even one on the wall circuit will be >50% ampacity (10.4 amps) and will require removal of all receptacles. Two just won't fit (20.8 amps).
So that means the bedroom lighting circuit can handle 1. (but the lights better be LED).
Use of the bathroom receptacle circuit is out of the question. That can only be used for bathroom receptacles OR loads inside one bathroom.
So we can't get there from here.
Since we have to run a new circuit anyway...
you can just run a 240V/20A circuit with #12 wire. That will be 4800W on paper and will support up to 3840W of heaters. (3840 x 125% = 4800).
Cadet baseboard heaters are laughably cheap. These are dog simple and will last 40 years.
2000W baseboard -- $65 due to demand, normally $50.
1500W baseboard -- $57 ditto.
1250, 1000 and 750W also available.
Add up to 3 thermostats at $15 each.
If you really want fan units, here's 3000W in one unit ($181) Or two 1500W fan units, $126 each. Or 1000W unit same price.
See how that "feature" doesn't make any sense when you know your voltage? It simply adds electronics that creates a failure point.