The most daunting steps are done. From here it's a matter of sliding gears and clutch hubs off the mainshaft. Be careful handling the mainshaft to avoid dinging any surfaces and be mindful that 1st gear is no longer supported to the rear.
With 4th gear, its bearing, and synchro removed support the mainshaft assembly with the front pointing downward. Again, there will be a small spacer between 1st gear and the bearing plate. Remove this and note its location for reassembly.
Like reverse, 1st gear and its synchro are easily removed and are supported by a needle bearing and inner bearing race. Slide 1st gear and its synchro off the back of the mainshaft being careful not to ding any surfaces.
Needle bearing removed exposing inner race:
Remove the inner race and flip the mainshaft around to work on the forward side.
As with the 5th/reverse clutch hub pull the 3rd/4th hub off from the front of the mainshaft. Again, it's probably easier to pull the hub apart to avoid damaging anything. You can use a puller but I used a 1/8" piece of flat stock that I laid on the hub surface and tapped with a hammer, alternating sides. 3rd/4th clutch hub removed:
3rd gear is like 5th gear in that it spins around the mainshaft with no needle bearing support. Slide 3rd gear and its synchro off the front of the mainshaft and the forward side is complete. Flip the mainshaft around one more time to get to the 1st/2nd clutch hub.
Remove the 1st/2nd clutch hub using the modified puller or by lightly tapping on a piece of soft(er) metal with a hammer, alternating sides.
2nd gear is like 3rd and 5th in that it does not have a needle bearing and inner race. Slide 2nd gear and its synchro off the rear of the mainshaft and the mainshaft is completely disassembled.
Note: Sometime in the early-mid '90's Mazda added a second synchro to 2nd gear in the Type M transmissions. This is seen in the pictures above. This does not affect the disassembly process but means there are more parts.
This is basically the end of the disassembly process. Assembly is really the reverse but with clearance checks and torquing fasteners required. Be sure to inspect all bearing surfaces, synchro surfaces, gear teeth, clutch hub teeth, and other parts per the FSM prior to reassembly.
Assembly note: to reinstall clutch hubs and bearings I made my own driver out of steel pipe. I purchased two 1 ft sections of 2.5 in. pipe and cut the threads off the end of one. I also purchased a straight coupler so I could adjust the length between 12" and 24" and an end cap to use as a hammering surface.
Short version:
Long version:
The next section is pretty much optional. I'll go into detail regarding the disassembly of the bearing plate and clutch hubs.