For question1, yes you have to have separate accounts for photography and retouching.
For your question2, post here for critiques: http://www.modelmayhem.com/t.php?forum_id=77,
that's the only place in here where you can get critiques on your retouching work.
About feedback from retouchers, in critique forum you can receive feedback from anyone, sometimes retouchers drop by there but it's not the case with every thread. Maybe you can try contacting retouchers you like that is they're interested in giving their feedback on your work, if you'd like to have feedback from retouchers specifically. I'm not sure if this method works but I received some PMs here asking for feedback so I came to know that this can be done.