I agree with #1. I'm still trying to get my brain around the different currencies - I looked into buying some steem on bittrex, but got confused with the withdrawal - what on earth is the "memo address" and "registered account"? Am none the wiser, so have left my steem there till I figure it out.
P.S. #4 markdown is exactly the same as on reddit. So for italics put a star around the words, for bold, two stars around the words, etc.
I had similar reactions when clicking on "Permissions". It wouldn't hurt to have a description next to each one of these so that we can understand what they are for. Then things got even more complicated after I changed my password and it was showing something else (hashes?) instead of what I entered. I was thinking "what the...?".
Everything within Steemit's platform is still being integrated and debugged. Hash is a number generated through a string of text.
http://www.thefreedictionary.com/hash
Simply withdraw to teatree from Bittrex. Memo field is optional for withdraws from Bittrex (deposits to Bittrex are mandatory so they know who sent it though). Registered account just means your account. They can't send to an account that doesn't exist hence "registered."
If the purpose of buying steem is to increase your SteemPower, go to your wallet page after confirming the withdraw, click on your STEEM balance, and select Power Up. The sooner you do this the better, as the steem supply always inflates but your steem value will stay static when it's put into SteemPower.
But which address is the registered one? On the "permissions" tab of my account I have four addresses - posting, active, owner and memo. Is "owner" the registered address?
Those are not your addresses. Those are access keys (similar to passwords). As arhag said, your address is just your account name 'teatree'
Transfers in Steem use account names not addresses (unlike Bitcoin and many other cryptocurrencies). So what Bittrex is looking for is the human-readable account name (e.g. teatree).