I had considered lock-tite, but then I thought since I may have to get these out again, perhaps that wouldn't be ideal, plus the tightening instructions don't call for it.

My new EGR Cooler was installed last night. Everything is running OK for now. I'll commute a few days and then I'm gone on vacation. Once I'm back, I'll take off the intake tube so I can access all the bolts and just double-check their torques to make sure it's all spot on. Cautiously optimistic.