....And the one who makes up his own doctrines to follow, too.
Yeah, like picking and choosing which doctrines in the Ordinary Magisterium to follow. Like you do.
A positive doubt about the validity of one's orders is not a doctrine. Therefore, avoiding those with doubtful orders is prudence, not generation of doctrine. Plus, it's one that would extend to the SSPX and Resistance as well, otherwise why would they conditionally ordain former NO "priests"?
There is no doctrine which states that Catholics are obligated to decide who is or who is not the Pope. We do not decide this for ourselves. It is outside of our purview.
Right, but Catholics are expected to identify other legitimate Catholics. And it is a doctrine that it is necessary that one is baptized and profess the true Faith in order to be a Catholic. Francis is certainly baptized, but he does not profess the true Faith.