Let me show you what I am doing and maybe we can work from there. I am doing pretty well on this lately and I think the idea has shown itself to have some possibilities:

Mon.

Squat up to heavy single
Assistance for squat (rack work at the moment)
Inman walk

Wed.
Bench up to heavy single
Bench assistance (headstand pushups presently)
KB clean and presses consecutively for high reps

Fri.
Deadlift to heavy single
Stack lift (like a rock)
Sled pull for distance

Sat. Repeat of wed. except for KP C&P's. Just extra work on bench and overhead pressing which is my weakness big time.

As you can see its just a matter of a powerlift that is not rotated or substituted, some assistance for the lift that is rotated around when it stops helping.

The assistance exercise could be a strongman thing too. Like a log press fits in fine with the bench upper body concept for the day and the stack lift helps you with the rock and is also one hell of a back exercise.

The last exercise is what I call "conditioning" but the Inman walk could just as well be a farmers walk or a Yoke walk also, or anything else. The KB clean and presses could be log C&PP's, barell lifts or thick bar C&PP's done for high reps.

This way I think the powerlifts and the strongman stuff compliment each other rather than taking away. you are getting plenty of work on the powerlifts but who is to say that "assistance exercises" must be with a barbell???...if you see what I mean?

It also gives you a chance to practice events and do explosive stuff that is also helpfull. In the evenings before or between other things I practice the flexibility stuff which sometimes helps recovery also.

I wish the contest were closer it sounds like a "hoot and a half"! I think you have time, just get out and do it, You will have a good time and find out all kinds of stuff you didn't know you didn't know yet ;-)

Bryce