Just bought a '96 T100 SR5 4x4 xtracab 5 speed 126k miles

This past week had timing belt, water pump, new tensioners, coolant flush, fuel injection cleaning, and changed all diff/tranny/transfer case oil.

1) Shop found 2 almost full teeth clinging to the magnetic drain plug on the front diff, no shavings in oil. Should I assume that they were consecutive teeth on the R&P? Should I install some manual hubs and just wait for it to grenade, then unlock the hubs so I can still get home? What kind of reliability do you think it will still have missing two teeth? The tech fished around with a magnet and didn't fine any other pieces.

2) When cold, truck idles high at ~1500 rpm with the clutch fan making a ton of fan noise until i get moving. After warming up, idle hovers around 1200 and sometimes drops to between 900-1000 rpm. Is this normal? I asked the shop about it and they said to get a tank of fuel through it and call them if it is still doing it because it could be from the fuel injection cleaning.

Any suggestions or help on these two problems?