That sounds like a great plan. The old tires should be able to support the car while you get things operating properly and safely.
I encourage you to wait until you are very confident that it will only be a very short time until you are driving the car. I made the mistake of buying tires and tubes way too early in the timeline to get my car going again. So when I started driving the car I already had “old” tires and tubes.
So for the next vehicle project we actually waited until tires were the reason we could not drive the car except slowly up and down the street.
| 
