Q: Could you have gone forward without the new guys? "Being a non-technical founder..." sounds like "no."
Q: What is their risk/investment level? (from your reply to taude) "They've agreed to a pretty sizable percentage of ownership. None of us are receiving a salary at this point."
Are they founders? IMHO YES!
The company was dead in the water or nearly so when the two original founders bailed. The company did not (most likely could not) pay the two new guys for their services, so they are at the same risk level as you.
Given that "founder" is a honorary title and (presumably) does not cost you anything more to confer on them, don't be stingy and don't insert a perpetual irritant where there is no need to do so.