Yes, of course. Deducible consequences. If a given theory is true then facts "A" and "B" should be observed, whereas facts "C" and "D" should not be observed.
If no arguments or observations logically entail any scientific proposition
Yes, because entailment/deduction runs in the other direction. Consequences are deduced from theories, leading to observations which then test the theory.
Reality is the final arbiter of all scientific claims. Facts have no significance in and of themselves, they simply are whatever they are. They are significant only with respect to their consistency or inconsistency with some theory.
Theories entail facts, but facts do not entail theories. Facts are objective and impartial. If you argue that facts entail theories then you rob facts of the neutrality that allows them to be used in testing theories.
You made a reference to Popper. Have you ever read anything by him? I find it hard to believe you have if you are having such a hard time understanding what I am saying. (Although maybe it is my own inadequacy in explaining myself.)