Dude, I think your on a great track.
The first time I did Whitney I was 290, and did 30-45 minutes on a stair-stepper 4 times in the preceding two weeks. I got crazy altitude sick but I got within 500 ft of the summit.
I think many people (under 40) are capable of doing it, they just choose how much they are likely to suffer for their lack of prep. I may stir the turd with that...
I think that you are off to a phenomenal start. If you'd like to add anything, make sure you do a couple of big hikes in the months preceding. I'd say 2-3 in excess of 13 miles and 4000' gain no further spaced apart from one another than 2-3 weeks. If you can, get above 9,000 in elevation that would be desirable.
Altitude has laid low many fit people who didn't acclimate well.
I would also take 4-7 days of rest before your actual Whitney climb (pending a small acclimatization hike the day before). If you're a quick recover (as cross-fit people are wont to be) maybe give 2-3 days rest.
