Retaining M5 bolts for bottle cages I have a Ti frame.

Alloy M5 bolts (they were greased) not working too well for me for holding the bottle cages - one seized / broke off, and I lost the boss/insert (?) when a mechanic drilled out the sheared-off bolt.

I understand that a light or medium loctite usually performs better than grease

However, are there any special considerations using Ti M5 bolts? (since in a moment of extravagance I have bought some, and currently awaiting delivery)
Sorry to hear about your bike...

Titanium anti seize is what you need. Park Tool makes one and you can usually find other brands of anti seize for a bit less at an automotive parts store but you may end up with a lifetime supply as bikes use very little.