I picked up a couple of used Fuji Ace road bikes for my kids (2014 Fuji Ace 650 and 2014 Fuji Ace 24).

Any recommendations on where to purchase spare tubes and replacement tires?

From what I can tell, the tires are 650c x 23 (23-571) and 24" x 1" (23-520).

Not sure what is a good brand....