No prob
@2Hover. Regarding Velocidrone and betaflight, velocidrone has a simulated version of betaflight PID configuration built into it so you can virtually tune the quad similar to how you could tune a quad in real life to avoid the nose dip when punching throttle or to change the responsiveness slightly, it isn't that big of a deal really but it is a nice to have and somewhat familiar if coming from or going to working with betaflight configurator and doing tuning there. Betaflight tuning section is a place it still sees pretty common changes/updates to things, most recently it seems to have been focused around the filters applied to the gyro data before it gets processed by the PID loop to remove "noise" (like motor vibrations from spinning on the arms) from the actual motion of the quad that the FC is trying to control and monitor.
OK getting into the weeds so back to the queries
Long story short yes any transmitter that has a USB connection for computer and shows up to computer as a USB Joystick (most of them and the two transmitters mentioned I'm sure would work fine). Most transmitters on the market now run OpenTX which is open source transmitter software that FrSky did pretty significant work on, but remained open source so a bunch of companies started building on the same software and similar hardware platforms.
Betaflight itself is just the firmware/software that gets flashed onto your FC using "Betaflight Configurator" another piece of software you run on your computer that handles updating the FC software and configuring it. Part of that configuration includes telling the FC what to do with the receiver input signals, the receiver is getting it's signals from the transmitter it is bound to so the FC (thing running betaflight) only has that indirect "view" of what the TX is sending along via the receiver, so really no compatibility needed between the TX and FC only the FC and RX need to talk and know the same protocol.
Hopefully that clears it up rather than making it more confusing but feel free to ask follow up.