Haha you all are great- thank you for the feedback. Truly appreciated as I am not an experienced international traveler.

I am constrained by dates - I would love to go a day early and have a buffer but I just can't. I have a high school graduation.

I can travel earlier in the day- it would involve a 16 hr flight from EWR or IAD to JNB. It would get me there a night earlier so no tight connection. That option is on United and would have to be economy - can't afford the $12k/pp or the 240k points per person. So it sounds like I'm risking it all for qsuites but I'm really trying to find a comfortable itinerary for such a long trip. BOS-DOH-JNB on Qatar qsuite / nonqsuite business vs BOS - IAD - JNB on economy are my choices right now, so if I can make it work, I will. But this conversation has given me pause and I am looking for alternatives. Might be able to pull of British airways BOS - LHR - JNB with more comfortable timing and a night before the VFA connection.

I am well aware of the risk of equipment swaps- don't see any way to account for that risk so I've let it go to the extent I can.