Tell me if I'm right:
*Marriage visa - fill one form, pay one fee and get to enter and work right away. file for an extention 2 years later if needed.
*Fiance visa - fill a form, pay a fee, enter, get married, fill another form and another fee (and does this include work authorization or is this a separate form and fee?) file for an extention 2 years later if needed.
You've got the process right....the "extension" you refer to is Indefinite Leave to Remain, which is permanent residence in the UK. If you're planning to do DCF back to the States, you'll need to have ILR, which means you'll be in the UK for at least 2 years + a few months if you do DCF right away.
If you want to marry in the States while he's there but don't want to send in his actual passport, you can have a
certified copy of his passport made and send that in instead, or his long-form birth certificate. Either one of those will suffice. It takes about 1-2 weeks (by mail) to process either a fiance or spousal visa application at the British consulates in the US. If you apply in person, it's same-day service.
More about the fiance visa...well, it's good for 6 months, during which time you must get married in the UK. You cannot work on a fiance visa. After marriage you fill out form FLR(M) and send in supporting documentation (basically the same as for the fiance visa, only with updated bank statements and things like that), and pay £335 (if applying by mail...you'll get your 2-year visa back in about 4 weeks) or £500 (if applying in person at a Public Enquiry Office in the UK...you'll get the FLR the same day.) After you've got FLR, you can work.
{The rest of this applies to both the fiancee visa + FLR and the spousal visa.}
Over the next two years, you'll need to collect all kinds of official mail addressed to both you and your husband, to prove you live in the same household (you'll need this for the ILR application.) You'll also have to pass the Life in the UK test, proving you're knowledgeable about...life in the UK.
Shortly before your FLR expires, you apply to stay in the UK permanently (ILR), using form SET(M). You pay another fee for that application (same as for the FLR.) Then that's it- you're done with UK immigration forever, unless you want to become a citizen after three years of residence.
