If I had to spend it on ebikes, I would build a completely new-materials version of SB Cruiser, using a middrive and a transaxle instead of hubmotors (possibly still with a hubmotor front wheel). Should be quite a lot lighter at teh same power levels, making for better acceleration.
If there was enough left, then also the enclosed and air conditioned trailer that could hold all of the dogs if I needed to take all four somewhere at once. (which could also probably be used to carry the trike itself in).
If i didn't have to spend it on ebikes, I'd buy dog food and dog stuff with it. Wouldn't last long with these four monsters--something like 90 bags of food that last about 9-10 days each, so a little more than a couple of years of food for them.