if two figures are on two separate rooftops, both at least 1 square away from the edge, but within each other's range, they still can fire on each other, regardless of that blocking line on the roof's edges, correct? thanks!

Yes, if they are both elevated, they interact normally.

"Yes, if they are both elevated, they interact normally..."

..even if they're not on the edge, correct?

Yup.

Yup...be careful counting out your range! ;-)