I think you are focusing a bit too much on legacy MIDI ports. Nowadays, the USB port provides all the MIDI connectivity you need, and push comes to shove and you have a dinosaur in your rig with no USB, there are inexpensive USB to MIDI converters.
Life has become a whole lot easier with USB!
Yes, if you are using a computer in between.
We are talking about USB to Midi , not Midi to USB. I’m not sure you are aware that it doesnt work in reverse.
Let me know if you have USB to midi converter without power supply.
There is none.
( Eg. using Yamaha P125 to say hook up SX900.
There is none unless you have converter box in between with own power supply.
There is a reason that Pros require midi outs in Live situation.
Not talking about this
https://www.sweetwater.com/store/detail/...mini-din-cable?Talking about this
https://www.sweetwater.com/store/detail/MIDIExpand--keith-mcmillen-instruments-midi-expander