Not a JUCO, but my son transferred after 2 years at a 4 year school to another 4 year school. His current school just cared about his GPA not his previous SAT scores. He did get academic money coming in. You can usually find on the school's website what scholarships are available and what the criteria is. I know at my son's school they have scholarships for kids coming form the nearby JUCOs. I think that's what they ended up giving him, because I didn't see any transfer scholarships.
As far as credits go, there was never a discussion of if he earned an associate's degree from his previous school. He was fortunate to have all his credits transfer (finance degree), but had to go back and forth several times with his advisor. In our experience it seems like privates have a lot more leeway with money and credit transfers.