Lowering gears and changing crank length on 1994 Bridgestone MB-5
There are some differences in chainring spacing between crank speed generations. But even within a speed generation, the spacing numbers are not truly standardized. That's one reason for the ambiguity you've found. Another is that with front shifting compatibility considerations on bikes in general, there are a lot of things one can do that fall under the category of setups that can be made to work but possibly with some level of compromised performance. Some voices you're likely encountering would think little of giving all those setups a stamp of approval. Others, such as those of us who do this for a living, tend to operate more in the realm of asking what will perform optimally or as-designed and disregarding everything else, because if we don't we're going to let people down and/or waste a bunch of time.

All that said, dropping in a 9 speed triple crank on a seven speed bike with a 7/8 speed chain and front derailleur is generally fine. So if 165 with a 22t small ring is what you want and you can find it in 9-speed, go for it. If it's another square taper crank, make sure to get a new BB of the correct spindle length unless it happens to use the same as what you've got. I recommend having some .6mm Wheels Mfg chainring spacers to tune things if needed, i.e. enough to put them under both the large and small ring to slightly increase the spacing if you find that your existing shifter and FD are producing too much total throw.

Also, in case it's helpful, 104/64 is the predominant modern MTB triple BCD. The smallest ring size the 64mm can take is 22t. One spendy but not all that difficult way you could go would be getting one of the various fancy interchangeable spider cranks, most of which come in 165 and have or have had 104/64 spiders available.