HOW DO I: Easily select the same take number on multiple tracks (Sonar Platinum)

Without looking at the video (ewwww facebook... lol) I'm gonna say what you are looking for is Clip/Edit Groups.
 
In the Record Preferences you can make it so that tracks recorded simultaneously are automatically grouped (like multi mic stuff like drums or three mic acoustic guits). That way when you edit one clip in one track all the clips recorded at the same time across all those tracks respond to the edit.
 
To set this up Right Click on the Record button in the Transport Panel to bring up the record preferences.
 
Underneath the Multi Track Grouping area select Group Only Clips In Folders (you could select group all clips but that's a little heavy handed... just read up on how it works).
 
Now create a Track Folder (right click in an empty area of the Track Pane and select Insert Track Folder).
 
Move all the tracks you want to respond to group editing into that folder.
 
Now record your parts and when you go to edit each take it's corresponding take(s) will respond to the edit.
 
If your tracks are already recorded you will have to manually group the clips. So select all the clips you want in the edit group > Right Click on one of them and select Create Slection Group from Selected Clips (and if you ever want to remove a clip from a selection group use the entry below that "Remove Selected Clips from Selection Group").
 
You have to do this ON THE CLIPS. The take lanes are just what contains the clips and the selection stuff is a little wonky so I generally avoid it.
 
Also be careful with selection groups in Comping mode. Splitting and doing comping stuff causes some odd behavior to edit/selction groups. Like you can totally screw up the group and turn everything into one big group or multiple big groups. Hard to explain. I need to analyse the problem further to see if it's a bug or intended usage but it has tripped me up before by totally ruining my selection groups. Then I'm forced to manually recreate the groups as best I can. Annoying.
 
Cheers.