I agree with the article in the sense that I would not add the "sucking in" maneuver with other exercises.

I disagree in the sense that I've read that abs crunches (and the other two exercises) would not hit the transverse abdominals afaik.

I also agree that multiple exercises are ideal, though I have trouble with irritating my TOS doing bird dogs in the class manner with the arm fully extended. That is very similar to reaching overhead which creates traction through my arm, shoulder and brachial plexus (which is fine if you don't have TOS). I've been thinking about doing a modified version where I keep the arm bent in some fashion.

I'd have to experiment with side planks to see if they were problematic.

I'm still a fan of the exercise I described and then leaving out that approach when doing other exercises.

Do you know why on the crunches they go with one leg bent? And then do you switch at some point?