The first one isn't much of a problem as I have quite some friends living in the US and I can forward mails to them.
when signing up, the site does state "Dwolla is currently only available to users in the United States."
dwolla's user agreement states: http://www.dwolla.com/dialogs/terms_and_conditions.aspx
You agree that you will not at any time attempt to falsify your identity
they could do things, such as freeze the funds until you provide u.s. identity though nothing like that has been reported so far.
Do you need a US bank account to actually use dwolla?
nope - you do not need to link a bank account to your dwolla account.
My intention would be to use dwolla as a payment receiving and payment sending option
why not just use the mt. gox redeemable code / voucher method for sending mtgox usds? it transfers instantly and is free.