The problem with figuring out how likely Magus and Schala would be to jump into bed together is that we know nothing at all about what sexual morality in Zeal was like--they might have permitted sibling marriages under certain circumstances, as some societies on Earth have historically done. Assuming that that was not the case, I could see Magus lusting after his sister, given that he's obsessed with her and certainly messed up enough emotionally. I can't see Schala returning his feelings, though--could you fall in love with someone whose diapers you changed?--and there is no way that he would try to force them on her. She is the one person in the entire Chronoverse who would be completely safe from Magus' violent side. (No, incest doesn't squick me particularly, so long as all parties involved are consenting adults. How did you guess?)
I didn't even think about that, actually. I admit, I said that mostly to see what the reaction would be - but as for my personal opinion...I don't know if I'm entirely for it, but I'm definitely not -bothered- by it. I suppose I could sum it up like this: "If it happens, sure, as long as they're both happy. I'm all for a happily ever after, hopeless romantic I like to think I am. But I wouldn't, like, push for it or anything." Yeah, I think that sums it up nicely.
(Okay okay, off the record or something, I can actually imagine it. It's even kinda cute. x_x Sadly. So shoot me. I really can just imagine it very well could work, given just how...damn -devoted- Magus is to Schala. At least in my view; I like to see it as no more than half revenge, no less than half outright loyalty to his beloved sister. Given how things must have gone for him up until he was unfortunately thrown forward in time, I can easily believe his sister was...literally all he had to cling to. She was the only person in his small universe that actually -cared- about him, from his view at least. So honestly, at least from his end anyway, I can see it working. He seriously loves Schala - whether or not in that particular way, we can only speculate, but he certainly does love his precious sister. At least I think so, anyway.)
And that, as they say, is...just a personal opinion. We can all go on about our lives, citizens...