Question 1 is possible, but not supported out-of-the-box by Marketo. There are two common ways to implement:
API/Webhook Solution - https://nation.marketo.com/message/110203#comment-110203 [the 'Recommended' way]
Question 2 is covered here: http://blog.teknkl.com/munchkin-2-letter-tlds-broken/
Sanford Whiteman can further assist, but these should be a good place to start.
Definitely read that blog post for #2!
For #1 the flowchart looks good but is pretty short on implementation.
The webhook way, while critical -- and simple -- for 3rd party forms such as SFDC Web-to-Lead, won't accomplish the same kind of automatic cross-association as the client-side way.