First off...great hog! Very fine animal and good job cleaning.
Do yourself a favor if you didn't seal it yet go out and get an aquarium heater, a 5 gallon bucket, some acetone, and some dawn dish soap. Crank the heater up as high as it can go add acetone, water, and dawn soap to the bucket and forget about it. Change the water solution once a week for the next few weeks. I can see some grease spots in the forehead and nose that will turn yellow over time.
It takes me no less then 6 months to do a hog/bear just for a time frame on degreasing.
As for the best method to clean that would be beetle cleaned, followed by maceration, then SIMMERING not boiling. Never boil anything greasy (bears, predators, hogs, etc)
For whitening get the strongest peroxide you can and soak the skull in it. 3% is the brown bottle stuff...the strongest most can get is 40vol (12%) but I buy 35% by the 55 gallon drum. Its rough stuff but it does a superb job. If you dont want to whiten and repaint the antlers either make a paste and brush it on or put latex over the antler burrs.
Soak in peroxide for 24-48 hours depending on the strength remove and place in front of a heater/heat lamp for an hour or so then set in the sun and for the day and it will be nice and white.