Q: After hitting a big puddle, car has whirring/grating noise in front of car. Also driver seat belt buckle won't pull out when cold

The seat belt retractor should be replaced as an assembly. It can be checked for obvious, and repairable faults, but generally an item like that which is safety related is not worth taking a risk over. Water can exert lots of force, and infiltrate parts too, so it is possible that components were dislodged and/or water has infiltrated something electrical or some component that turns. As you describe it, the noise is marked and obvious enough that if you request a front end inspection, the responding certified mechanic will quickly pinpoint the origin of the noise and get this resolved for you, right at your location. That same mechanic will advise you as to the set belt retractor assembly issue, too. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.