Thanks in advance for your help!

For May 2024 trip, I had booked a QR flight using AA miles to Windhoek, Namibia. But Qatar has just recently stopped flying to Namibia and they cancelled my last leg DOH-WDH. The AA agent I spoke to said I could get DOH-JNB or DOH-CPT then have to buy my own ticket from there to WDH.

After research, it seems like the best (cheapest, on time record, and time wise) is Airlink JNB-WDH for ~$120. This would mean 2 separate PNR.

From reading online, it seems Qatar has an agreement with Airlink. For example, if you buy ticket on Qatar website DOH-WDH - it will be DOH-JNB on Qatar then JNB- WDH on Airlink. But my flight was booked using AA miles so according to the AA agent, they can't put me on Airlink since it's not one world.

My questions are these:
1. Would I need to clear immigration? or do you think Qatar can do interline baggage with Airlink so I don't have to pick up my baggage in JNB?
2. IF I need to pick up my baggage and clear custom, how long should my layover be (minimum) in JNB to be able to clear custom/ immigration and catch my next flight?
3. Anyone knows if Qatar is going to fly to Namibia directly anytime soon? It seems like they were going to come back in March 2024 but I looked on their schedule and I don't see any direct flight in May 2024.