Again, problem with that Pablo. None of the parts you are referring to exist in the US. There is a lot of stuff in the European markets that is not available in the US.
There are no bolt on conversions to mate a 3.0L or 4.0L to a T5. There is a bellhousing to mate a 2.3L to a T5, in fact those are pretty easy to get here.
If you have the ability to fabricate a custom bellhousing, its not that difficult, but mating the Dana28 is a bit more complicated.
The only manual trans that will mate to the 3.0L or 4.0L easily is the M50D manual trans from the Ranger, but that is a major downgrade from an A4LD. The M50D is plagued with weak gears, sloppy build quality, lousy synchros. If you are gonna go through the trouble of converting to manual, the T5 is the best way to go, getting something that is weaker than the stock auto.
But a properly upgraded A4LD does not have to be expensive, and because its what the vans came with, there are no adapters of any kind needed.
M5OD is used on Mazda E series vans. Small Asian van.. there are in use in Lugansk as EMS vehicles for narrow urban areas. And I know that tranny is not so good. too many problems with noise , OD and countershaft wear.