Are answers based on the Samaritan Pentateuch considered as being answers?
I don't think we'd allow answers based on the New T.
Case in point: This answer. Fascinating answer, but not based on traditional sources.
I think that we should not accept answers that draw religious authority from sources not known to be Jewish (which includes those known not to be Jewish). Who is (or isn't) Jewish can be a thorny problem and I am not talking about Jewish pluralism here, but if a group does not even claim to be Jewish, that would seem to qualify as a "no". (Claiming to be Jewish might not be enough for "yes", but our community should discuss specific cases as they come up.)
However, answers that use information from such sources, without treating them as authoritative for Judaism, are ok. (Of course sources should be clearly disclosed, but that's true for everybody.) These might or might not be good answers; that's what votes are for.
A halacha answer based on the gospels or Christian theologians: no
A history answer about second-temple-era Pesach practices based on the gospels as historical accounts: yes
A history answer about second-temple-era Pesach practices based on Josephus: yes
A halacha answer based on Samaritan sources: no (because they don't claim to be Jewish)
A halacha answer based on Karaite sources: I don't know, see also here
A halacha answer based on J4J sources: no (they claim to be Jewish but we explicitly reject their claim)
A Tanakh text-interpretation answer based on rabbinic tradition: yes, duh (this is just here for context)
A Tanakh text-interpretation answer based on analysis of ancient languages, lexicons, and other secular linguistic work: yes
A Tanakh text-interpretation answer based on the Samaritan Pentateuch, Dead Sea Scrolls, or other contemporary sources: yes
A Tanakh text-interpretation answer based on faulty translations such as some Christian ones: yes, but downvote (wrong answers are still answers)
Any answer based on known-fraudulent sources: no (we should not be a platform for spreading such material, even if heavily downvoted)
As far as I know, this meta post is our canonical post about the on-topic-ness of non-rabbinic Judaism. There doesn't seem to be a clear-cut consensus on the topic, but msh210's answer to the question does provide a guideline that AFAIK we generally follow. The answer there quotes an answer to a different question which says:
Thus, it cannot be "Can someone explain this practice of Mysect Judaism?" where Mysect Judaism lacks Jewish-tradition-based sources that discuss the question.
msh210 continues to say:
As far as I can tell from what little I know about Karaite Judaism, that last paragraph applies to its practices directly where such practices differ from mainstream Judaism's, or at least to most such. Definitely this can be decided on a case-by-case basis, though.
The above post is talking about questions rather than answers but I think it can be generalized to answers as well. If questions about non-rabbinic Judaism are out-of-scope when they ask about such practices as differ from mainstream Judaism, so too answers from the perspective of non-rabbinic Judaism are out-of-scope when that perspective differs from non-mainstream Judaism. I think that will include pretty much all answers from the perspective of non-rabbinic Judaism since if that perspective agreed with the traditional perspective, there would be no reason to answer from the non-rabbinic perspective.