I know there are cranks available but long cage rear derailleurs and shifters for a triple are gone. Shimano makes Tiagra, SRAM and Campagnolo have abandoned it. Plus Shimano front derailleurs seem to work best with a 53T big ring. Their MTB fronts are not compatible with road shifters. I am not interested in barcons for this build. Sadly I seem to be SOL.
Depends on what you want to do. For an 11 speed transmission you are probably SOL. But 10 speed and 9 speed are still an option. Shimano still sells the
Deore mountain bike derailer in 9 speed. It will work for 10 speed with 10 speed STI shifters.
Microshift makes triples stuff in 8, 9, and 10. They have shifters as well as front and rear derailers in all three. Perhaps not as good as Shimano but I’ve worked on bikes with Microshift and they seem to work fairly well.
I think you are being overly broad on Shimano front derailers. I’ve used Shimano fronts on outer rings as small as 46 teeth without problems. I would suggest that you don’t look at
any of the higher end Shimano front derailers, however. The higher end Shimano front you use...road or mountain...the more finicky it is. Shimano’s Tiagra or below fronts work well and are easy to set up. 105 and above have issues. I’ve use Tiagra and Sora, as well as Microshift, and have had very good experiences with them.