I suggest its clone, Double Commander. Does everything as TC, supports its plugins and is cross platform and open source. I was very active in TC community until I switched to DC.
Is it possible to show a dialog at startup that waits until I press one of the 1-2-3 buttons?
Yes, I know about it and it's good. But since I already paid for TC the only reason for me to use it is that there's a Linux version, which is nice.