So your drum brakes work fine on the 69, but you're wanting to convert to disc from the 72? Is that right? I'm not sure what condition your brake lines are in, but if all else is good, you should be able to just switch the master and prop valve, hook it up and bleed the system. I'm not 100% certain the brake line sizes are the same, so you might have an issue connecting the existing brake lines to the prop valve. As for the booster and MC working together, that shouldn't be an issue. I believe the only thing you might have problems with is the push rod length, assuming one is manual and the other is power brakes. If they are both power brakes, they should swap just fine.
Please keep in mind that I haven't done this exact swap, so I may not be right. But the booster is the same for 67 to 72 so theoretically it should work without incident. Check this out:
http://www.summitracing.com/parts/aa...up?prefilter=1
According to Summit and A1 Cardone the booster is the same for 67-72 C/10's.