I agree that a strong European bid wouldn't be easy to reject after these years, even if it's with another double award, and I'm actually quite surprised that although the Spanish NOC President really wants Madrid to host, there haven't been any serious talks about a possible bid so far. They may be waiting for the local and general elections in 2019 and 2020 to make a decision.
As for Indonesia, I always like seeing new hosts. They now have the experience of the Asian Games but it also seems that Jakarta as a city isn't as attractive as other possible non-traditional candidates like Cairo or Mumbai/Delhi, so I wouldn't know what to expect if it was between these three. The good news for the IOC is that there are already more cities interested in 2032 than there were for 2024.