...the connections and similarities in imagery, symbolism and even belief structures are undeniable.
Yep.
I think it's important to identify which direction the connection goes though. The cross and crown for example is used by Catholic, Lutheran, Methodist, Episcopal, Presbyterian, Baptist and Chrstian Science churches today. Did these various Christian denominations acquire the cross and crown from the Masons or did the Masons acquire the cross and crown from Christianity? Which is the "Cart" and which is the "Horse" here?
Same thing goes for the Knights Templar. They were originally a Christian order, so it's not a surprise that they would use Christian iconography. That does not in and of itself establish that they were the source of it. (As opposed to simply borrowing it from the church.)
The use of insignia and emblems from medieval Christian/military orders by modern Christian groups is even more convoluted vis a vis the Masons because there first needs to be a legitimate connection between them. Are the Masons directly connected with the medieval Knights Templar? I've watched the videos that people post here and read the books I could find and had a good laugh. Sizeable historical gaps invariably get filled in with crap from the author's imagination.