1. The address thing. How do I settle that? My Fiance mentioned something like this, about getting onto property tax or something and having my name on the address? Or is it as simple as having a relative send me something to that address or does it NEED to be like a bill or something?
No, it has to be something official like a bill.
You just call the council/utility companies and ask for them to put your name on the account, then wait for them to send you something in the post.
2. My Honeymoon is abroad actually- Barbados to be exact...oy...I did not know this bit. My visa DOES say multiple entries on there, but I do see your point about the part "Being married" BUT would they know? unless i haven't registered for the FLR (M) yet...is that what you meant by go on honeymoon BEFORE applying for the remain to stay?
It is multiple entry... before your wedding. After you are married, it's a bit of a grey area... technically, since you will now be married, you are no longer eligible to enter the UK on a fiance visa.
Whether or not this is an issue for getting back into the UK will depend on the immigration officer at the airport... you have to tell them the truth and if they ask when the wedding is and you're already married, that could be an issue.
You can't travel while your FLR(M) visa is processing, so really you need to have applied for AND received your FLR(M) visa before you try to travel.
3. We are ok to set up an appointment 6 weeks even before getting married then? That helps, BUT should I even do this if I am going abroad for honeymoon? I should JUST wait then so that i can still have my "Fiance Visa" come back and then apply for appointment?
You must be married on the date you attend the appointment, but you can book the appointment before you are married... you just have to book it for after the wedding.
For example, if you are getting married on September 24th, you could book an appointment in August, for a date after September 24th.
If you cannot change your honeymoon dates, you might be okay risking it and travelling to Barbados, hoping you don't have any issues getting back in, and then attending an appointment for FLR(M) after you get back.