Do these mount to the original headlight buckets?

Yes—they're designed for factory mounting points. No drilling or bracket modification needed. Just unbolt the old sealed-beams and bolt these in their place.

What bulbs do I need?

Bulb type is not specified with this set. Check your vehicle's service manual or the housing itself for the correct H-series or 9-series bulb designation, then source separately.

Are these sealed or do they need adjustment after install?

Once bolted to the factory brackets, aim them the same way you would adjust factory lights—use the adjustment screws on the back of the bucket. Most cars have vertical and horizontal trim screws for alignment.