Finally, a question I can answer!! And in more detail than you ever wanted...
For sounds, believe it or not, the GP38 sounds are accurate for all early EMD engines (if memory serves: GP and SD 7-18 and 38, F-series through F9, all E, SW and MP series). Unfortunately you don't get the neat "gunshot" sound as the engine accelerates, but oh well.
For turbo EMDs (GP/SD 20 and above (except 38), F40/45), try 645e3_10.zip (from train-sim.com) which has a neat startup sound (yes, they really do sound like that when they start, and they whistle like a jet plane all the time). The SD40-2 sounds with MSTS 1.2 are close but not quite right (the turbo whistle really overpowers the "beating" of the engine). The sounds that come with NALW's F40 are good (the HEP version has the engine running max RPM all the time, which is how Amtrak did it). I believe some of your British EMDs use the 645 engine, sounds are the same.
For older Alcos, NALW's PA comes with sounds that are OK; I've only heard them run IRL a couple of times. What Alcos are famous for is LOTS of smoke till the turbo spools up, too bad MSTS can'd to that. I would imagine that older GEs don't sound much different than the Dash9.
For cabviews - again, EMDs are my area of specialty. F/E (through 9) and GP7/9 use the old "drum" style controller; in the late 50s they switched to the "console" type shown in the GP38 (imperfectly - the controls aren't in front, they are at the side. The MSTS v1.2 SD40 cabview gets the proprotions about right.)
For E and F units, you cannot beat Train Artisan's cab (
http://www.trainartisan.com) but I think you need to join Club TA to get it. F7acabb.zip (two B's, not a typo) and the update f7acvf.zip will give you a somewhat correct cab; f7acab11.zip is a nice view, wrong controller. fp-f7cab.zip is neat, it has the brakes and gauges right but the console controller instead of the drum. BTW, I believe the real F cab had the controller to teh driver's left, locomotive brake directly in front, train brake valve to the right.
For older high-hood EMDs, try gp7cab.zip. Proportions aren't quite right but the controller is something like the drum-style. Vision out of those things was better than the cabview shows. On the real thing, the drum is just to the left and ahead of the seat, with the brake valves next to it (actually sort of behind it).
For older EMD switchers, emd_swch.zip is close enough (wrong controller). Later switchers have rectangular windows at the center, not domed. SW1500 models seem to come with cabview that is about right for it as well as the SW1000.
f45cab.zip is a nice cab for F45 and FP45, plus some other "safety cab" EMDs. NALW's F40PH comes with a good cabview.
Occaisionally, older EMDs (and some non-EMDs) would be rebuilt and would get console-style controllers and 26L brake equipment (the kind seen on GP38/SD40).
For Alcos, I have only seen pics of the carbody cabs, but I think NALW's PA cabview is about right. The RS-3 cabview rs3cab11.zip also looks about right. Speaking of that cabview, remember most older high-hood locos ran long-end first for collision protection. The exception is the EMD GP7/9/18; they were a mix (look for an "F" at the stepwell of any American diesel to determine front). Southern Ry (and later Norfolk & Western) ran stuff long-end first until a few years ago - even after EMD or GE stopped building them high-nose locos.