Try a waterbased sealer followed by a few coating of waterbased finish. These have very low voc's and each coat dries in about an hour. So generally you can do all of the coatings in one day. After applying the sealer it is not necessary to buff before the first coat of finish, but it is required btween the 2nd and 3rd coats. If you are not familiar with running a buffer, you can just use a pole sander that is for sanding drywall.
There are water based floor varnish that are very low in VOCs and much more friendly that oild based varnish. Water based polurethane would be about equivalent to paint for off gassing and look much better.