That’s no mystery at all. The 32bit package comes from the same repo as the 64bit one.
There are no specific repos for 32bit/64bit (i586/x86_64), zypper chooses itself which version to install.
In your case, it couldn’t install the 64bit version because of the conflict, so it tried the 32bit version instead. This gave a conflict as well, so it reported that and asked for how to resolve it.
And you can run 32bit applications on a 64bit system. You just need all dependencies in 32bit as well, and the question is whether it will make sense if there is a 64bit available.
In this case, the 32bit version wouldn’t have worked anyway, because of the missing ncurses update. Exactly the same as for the 64bit version.
I use your factory frameworks repos by the way.
Should I go back to your tumbleweed repos?
That’s irrelevant in this case.
And both should work fine.
But I’ll shortly describe the difference:
The Factory flavour is built against KDE:Frameworks5, while the Tumbleweed one is only built against standard Tumbleweed.
That means that with the Factory repo you absolutely need the KDE:Frameworks5 repo as well, whereas for the Tumbleweed flavour no additional repo is needed (just add my repo to your standard Tumbleweed system).
Otherwise there’s not much difference, as the packages from KDE:Frameworks5 are submitted to Tumbleweed anyway (KDE:Frameworks5 is the devel repo for Factory/Tumbleweed). But as they need to go through testing and are only published if the whole Factory/Tumbleweed passes all tests, this needs a few days, simetimes even weeks. So you’ll get new KF5 or Plasma updates some time later.
E.g. at the moment Plasma 5.2.1 is being prepared in KDE:Frameworks5 (and in my repo), “Factory” will get it on Tuesday. They will probably submit it to Factory/Tumbleweed on Tuesday as well, but you will only get it a week (or something like that) later in the Tumbleweed repo.
KF 5.7.0 is available in KDE:Frameworks5 since 2 weeks already. This has been submitted to Factory/Tumbleweed back then, but only was accepted to Factory/Tumbleweed 6 days ago (after review/testing).
In the end you have to choose what you prefer.
Factory is bleeding edge, Tumbleweed is the same after testing/review, but that testing/review process causes a delay.
Not that it makes much difference for the additional applications (those that are not available in KDE:Frameworks5 and Factory/Tumbleweed) in my repo though, those are bleeding edge/unstable git snapshots anyway… 
PS: OTOH, if you choose to use my Tumbleweed repo, you should not add KDE:Qt5 nor KDE:Frameworks5 repos and should rather remove them. Else you will experience temporary problems when KF5 or Plasma5 is updated.