All the Middle Eastern, North African, and Eastern churches with roots in antiquity pray to saints, too, as did Jews to OT saints in late Judaism--hard to account for if Rome made it up. And I have already cited Scriptural references to the practice in Hebrews and Revelation.
Not in the earliest centuries -- the first two, at least.
Do not confuse prayers about, and concerning the dead with prayers addressed TO those same.
Are there Jewish sources to back that up? Referencing a handful of articles written in German doesn't quite cut the mustard.
Your arguments are exceeding flimsy. 'Tis a pity you can't see it. Then again, it appears to me you don't want to see it, since the aim is to justify and protect theological developments -- or else -- one would need contemplate that the Latin Church is not the center of OTC®, and over the centuries (along with most any other ekklesia) has allowed various ill-founded theological considerations to become part-and-parcel of their own theological outlooks.