Alright, we're running.
I never did figure out what was making that sound, but I did pull both of the covers to make sure the tensioners were good.
I got scared about that idler not being centered on the piston and spent a solid hour fretting over it before just moving it with a screwdriver. (I probably should have replaced those chains, but it was a different world two & a half years ago when I started.)
I got my injectors back from RC Engineering. They took just over a week including shipping to CA. They even re-painted them (albeit a different color). I wonder how they got those stuck ones running, I was fully expecting to have to buy some more.
So after the startup and breakin run which sounded fine, I went to back it into the garage and it felt like it had a dead cylinder. I hope I get a chance to pull the plugs this week. Thanks again for everyone's help. I was really scared I had done something wrong.