That much slapping around sounds like either the tensioner failed outright, or he forgot to pull yhe pin out of it.

As far as that top guide goes, even IF the OP forgot to tighten the bolt, I don't think it would make that noise. Those straight guides are just to keep the chain steady, and I've seen engines that had those completely broken apart, running for years with no noise.
For the record, though, they weren't 4.6s, so I could be wrong on this.

Definitely did not forget to pull the pin, haha. I'm guessing I didn't position the passenger side cam correctly when I pulled the pin.

When I put the chains on, the drivers' side lined up perfectly. On the passenger side, there was slack on the straight guide side unless I rotated the camshaft backwards slightly. It's my hope that if I orient the chain CORRECTLY this time by carefully rotating the passenger cam, then pulling the pin, it should eliminate the slack. Obviously I need to be extremely careful not to bend a valve. Risky territory for sure.

You should rotate the crank shaft several time by hand , you will see right away if you have PTV issues .