Regardless of the internal you use, for parts it will come with its own axle, and you can't use any of the ratio-altering parts without the axle, so you are basically looking at swapping the entire internal.
It is possible to install the AM internal into most (old style, i.e. non-NIG type) AW hubshells.
However this internal was only available with axles that are (by modern standards) rather short, so maybe it won't work in your frame.
If you have a more modern (non-brake) AW hub (with 'NIG' internals) the AM internal will fit in the shell but may not drive correctly in the low gear; the drive ring in the left side of the hubshell is slightly different. You will have to try it and see.
Re 5s parts. The recent ****(W) 5s internals (2009-2016) have the middle three gears spaced like the AW, so there is no point. [They don't fit into the AW hubshell either.]
The previous 'single toggle' 5s hubs (1993-2008) have closer gear ratios (not as close as an AM) but the internals only install into their own dedicated hubshells.
The twin-toggle 5s hubs (and the FW four-speed) have the same gear ratios as the single toggle hubs above and the internals will fit into some (but not all) old style (i.e. non-NIG type) AW hubshells. The clash occurs because the LH bearing housing protrudes into the hubshell too much in some versions. I think all the more modern AW (NIG type) hubshells have the same issue, but I'm prepared to be proven wrong.
So if you buy an AM hub (complete) you can try the internal in your hubshell and if it doesn't fit you can rebuild the wheel. AM hubshells are usually 40h. You can still get 40h rims (with difficulty) and it is also possible to build a 32h rim onto a 40h shell using only two spoke lengths. Of course an older AW shell in 36h could be found that will accept the AM internal instead.
Similarly an FW hub might work for you. Same 40h issues. You can use the hub with a 3s trigger to give gears 2,3,4 as is, or you can convert an FW internal so that the lowest gear is not available; for this you need an (old style) AW toggle key and a matching AW control rod. These parts will also fit into an AM. [Given that new control rods for FW and AM hubs are hard to source this is just as well.]
One note of caution is that the 4s/5s gear ratios are only about 5% closer than in the AW. This does make a difference, but it may not be enough of a difference to be worthwhile for you.
There are other hubs that might work for you (e.g. FM) but they are difficult to find and spare parts are again not easy to source. FM internals must be used in the matching hubshell.
hth
cheers
