4F or 4C? 4F is fine, 4C might be a bit of a shock but I dont think it would cause any harm.
Unless your water parameters are very different a 2 hour drip acclimatisation is a bit much, and if your fish are delivered it might be harmful.
Ammonia will build up in the water during transit. But the fishes respiration, removing
O2 and adding
CO2 will acidify the water. Ammonia is much less harmful in acidic water. You open the bag, the
CO2 offgasses, water becomes less acidic, ammonia becomes more toxic. Your fish is now in toxic water for the drip acclimating period.
When your fish are mail order its often safer to get the fish out of the water as quick as you are able once the bag has been opened. Temperature match the bag by floating it in the aquarium for 20 minutes, open the bag and get the fish in the tank ASAP.