From what I've seen you should be fine doing QR with the SS, no matter what since your chain ought to keep your wheel from falling out the back and even if the QR does slip forward the worst thing it will do is contact the brakes or ST and your just slow to a stop.

Someone correct me if I'm wrong - there might be other problems with that setup, but AFAIK you ought to be fine.

As for #2, chain tensioners might help (?) but probably aren't necessary. As for #3, many hubs use a standard axle that can be changed out one way or the other, if you've every used a cone wrench you can do it yourself.