I will post this answer until someone tagged as an expert can possibly give you a much better answer. This kind of falls into "what-if"/speculation history, which is difficult to determine at best and leads to a variety of answers. That said, to the best of my knowledge, no, I don't think the founding fathers could have both fought the Revolutionary War and freed slaves at the same time.

The division between the North and South regarding slavery already existed during the colonial and revolutionary period. While slavery existed in the North, it was a society with slaves while the South was well on its way to becoming a slave society. The South already required large amounts of slave labor to run their plantations and the idea that Southern leaders would willing fight a war that would require them to free their slaves is, frankly, ludicrous. It's completely outside of their self interest. The North already had a difficult time persuading some colonies in the South to rebel- requiring them to free their slaves, even 30 years from then, would have left many of the Southern colonies on the British side. The South was a huge exporter of raw materials and commodities like sugar and tobacco to England (by default, England was their sole trade partner) and asking them to make war against their only market (outside of the north of course) was a tough decision for many Southerners and plenty of them didn't join in the rebellion. This isn't to say that support among the North wouldn't​ have been weakened if they were also required to give up their slaves, but in a slave economy like the South, it would have been a non-starter for most land holding men because slavery was already so vital to the South.