You SHOULD absolutely compliment the Tupler Technique with other exercises!! Anything aerobic is GREAT! Walking, Running, etc.
Yoga is mostly fine - just watch how you get into and out of postures - no jacknifing and avoid the abs they do.
Pilates is full of quagmires for getting your diastasis back together - avoid it for several weeks until you know HOW to modify things that can backtrack you back to step 1, or make you worse, like Pilates 100, Corkscrew, Teaser, /Scissors, Saw and (of course) Jacknife. I will modify a few of these for my clients - like Pilates 100, Scissors, and Teaser, and avoid doing the other ones ALTOGETHER!
Eliptical is great, Treadmill is great...
Crossover movements - like punching (with kick boxing), golf and tennis until your diastasis is all the way back together. Avoid lifting weights until after you have strengthened at least 4 weeks so you don't undo any of the work you are doing to heal your diastasis.
PLANKS - be CAREFUL, be CAREFUL, be CAREFUL!
- Doing the side plank you will want to not put both feet all the way extended - bend one leg to support yourself with and extend your body and the leg on the top, keeping the transverse to the spine.
- Doing the plank where your belly is parallel to the floor can be VERY hard on the transverse that it can't engage very easily. Avoid until after you have been through the 6 week program and/or have closed the diastasis, and even then have CAUTION because with the gravity factor can be hard, as well as the strength demanded by the transverse. Even seasoned Tupler Techniquers beware of this one. I would drop ONE knee and bend at the wrist rather than the elbow and get the same extension of the body.
Have any specific exercises you have questions about? List them in the comments section and I will tackle them for you!!