Personally, I'd not let the 1ph thing bother me. I'd go w/a phase converter then 3ph all the big motors. Maybe you can add a 2nd converter if needed. "Here" getting 3ph any more is almost history. 20 yrs ago it was different. But-again, that's "here".

Those rates & programs that companies have are "today". They can change their policy in future & you'll have a completely different program. Especially if any of them are co-ops.

That's me. But, it's your $$.