Welcome to the community MacQ.
Questions:
Is the MRS-DXB-CAI backtracking?
No. All three are located in IATA2 and there is no such thing as "backtracking" per se on a :-: RTW except for IATA2 to IATA3 and the two oceanic crossings for the most part that you have to be mindful of when thinking backtracking.
How many stopovers and transfers are allowed each city? I didn't see any other posts of recent vintage for this.
You are allowed 3 transfers per city (incl multiple airport cities like NYC) of which only 1 may be a stopover of more than 24 hours if you want one.
Is the Jan 1 2005 edition of the RTWMC fairly reliable? If it says my route is valid can I pretty much bank on it? (ignoring confusion re: SQ EWR-SIN and similar flights)
Couple of minor glitches but okay for the most part from what I've seen on it so far.
For your itinerary you have the three minimum stopovers, so as long as you meet the minimum stay away for ex NthAm RTW's seems good to me. Someone else may pick up on something I've missed.
You are, however, only *just* a smidgeon over the 26,000 mile mark putting you into a :-: 1 rather than a :-: lite fare bracket.
Swapping FRA for MUC on the MRS-DXB portion will cut 203 miles off and routing MCO-PHL-FRA gets you another 50 odd miles saving from the current routing. If you play around a bit with the routings, you are bound to find something to get the handful of miles left. Is MIA-FRA to start the trip an option ??
With the itinerary from the MC, any advantage to using a travel agent w/booking fees rather than direct with airline? If my travel agent has never done a RTW, would they add much value?
The only things an agent can make easy over an airline is allocating/requesting seats on each carrier as well as meal requests etc. If it's an agent that deals in consolidator fares they may also be able to pro-rate the journey getting a slightly cheaper fare.
Is there a place with all the detailed current RTW rules?
Try the following link. Not sure if it's been updated with the most recent rules release a few weeks ago but it has been accurate in the past. It's maintained by one of our stalwarts here in the forums.
http://members.shaw.ca/deercroft/StarRTWrules2004.doc