I have 2 aeroplan bookings on TK. I was able to find the TK PNR for both on cowtool PNR tool.

For 1 booking that has 1 passenger, I was able to load it up on TK app and select seat.
For 2nd booking that has 3 passengers, it's asking me for the 235 ticket # of each individual passenger in addition to the TK PNR #. Is there any way to find this ticket #?

edit: nevermind.. using the 014 AC ticket number of each passenger worked