I agree that it takes about 90 minutes from when you arrive at the ME loading area at MCO to when the bus will drop you off at your resort.
I disagree that you should expect it to take 90 minutes from when you arrive at the DME area until your resort drop-off.
The average reported time from DEPLANING to resort drop-off is 70 minutes. SO that 70 minute average includes walking from the gate to the monorail and then waiting for and riding the monorail from the airside to the terminal and then walking to the DME area, and so on. 90 minutes from arrival at the DME area is certainly possible but would be pretty darn unlucky.
Like I said, the average time from deplaing to resort is 70 minutes. I timed it on each of my trips, and it's ranged from 56 minutes to 63 minutes for me (an average of a hair under 60 minutes for me).
As for the order of drop-offs and the grouping of resorts ... there are is no pre-set grouping of resorts and no pre-set routes. Resorts near each other tend to be grouped together becuse that is usually the most efficient way, but if other resorts in your area don't have guests heading there around the same time you are, then your bus will have resorts NOT in your resort's area. There are 4 geographic DME zones. If your bus will drop off only within a single zone, there's a maximum of 4 resorts per bus. If your bus will drop off in more than one zone, then there's a max of 3 resorts per bus to make up for the increased driving time.
The driver actually gets to decide the order of drop offs. They are told which resorts are on their bus, but they are free to drop off those resorts in any order they want. The only hard and fast rule involves Polynesian Resort, however. If there are both Poly and Grand Floridian guests on the same DME bus, the bus must stop at Poly first, no exceptions. This isn't some Disney preference of Poly over GF, but rather is due to logistics ... Poly and GF are both on the right side of a dead-end street, and if the bus stops at GF first and then has to drop off at Poly it won't be able to make the left turn into the Poly complex without stopping and backing up and then going forward again (a K-turn). You can imagine the problems that would cause, and as a result ALL buses (DME as well as Disney Transport and
Disney Cruise Line) MUST stop at Poly first if they are also stopping at GF.