I think Flying Clouds now all have full-opening windows. From spring 2005 until FCs were introduced, a Safari had to be an SE to have these windows. Otherwise you are correct - Classics and Internationals do too.
Nope, we went straight from our Argosy to the 25' FB SE. Six-sleepers are six-sleepers in theory if two friendly small kids sleep on the dinette and 2 sleep on the gaucho. And then you have to have two adults of moderate height who've tested out that the corner bed works for them. In my experience kids like tents if they want to camp at all, which obviates the need for six sleepers. I've seen a DVD-using 16 year old "sleep" in a truck and its batteries were dead in the morning.