Great info, Pat.
Let me add that many Deore/MT/6206 triples will work fine with a 3N or 3P 119mm asymmetric spindle; new nutted versions are available for under $10 online. Agree that they are not as nice as a a shiny Shimano or Phil BB, but properly installed and adjusted they’ll result in a nice smooth rotation.
With regard to RD’s, virtually any Shimano long cage RD will do the trick and properly index interface with your shifters, or can be friction shifted. The 5500/5500/5700 series in particular are robust, relatively inexpensive, and there are replacement pulley wheels out there for cheap. Cage is not too narrow for a 6-7-8 speed chain.
FD’s for a triple can be tricky, but a Deore/MT from the 6-7-8 speed period can handle it, plus they are often 28.6 clamp models.
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