Powerlifting and weight management...

Just cut back a bit on the food and do some cardio! It won;t affect your lifts because you are not looking at getting super lean just stopping yourself from getting fat! Getting bigger makes you stronger...getting fatter doesn't so you need to be honest with yourself. Alot of PL's drop weight to make a weight class and still break world records! 

I would add cardio 1st on other days but I have done and will do again cardio after squats and deads but only steady state stuff. 

If you can do 50 reps sets on abs then they are not heavy!
 
You do the stepper holding plates? Why not just change the settings? And what are the push ups for? It seems to me you have a bit of a mish mash training.
 
If you read my post I said I would add your cardio 1st on other days (as in not squat or deads). I think 30 mins to start with should be fine. If you are getting fat then you have to either up your output or cut back on your input! Just because you want to powerlift doesn't mean you have to give up the ghost on looking good it just means that being ripped is not a sensible option.