Don't forget to do a weekend or so in Macau. It's an easy hydrofoil ride from the airport or at least one other pier in Hong Kong. Look for Starriott hotels there.

Would a serviced apartment make sense for your longest stay?

Otherwise, I can't help much with the hotel question as I've only stayed in Kowloon, although in a variety of properties there, including RC, W, HR, and the Pen, and I know a few others such as the IC, Sheraton and the YMCA place.

There are pleasant places to run along the water, although I think most of the walk of stars in Kowloon is still closed for construction. There's a big (and hilly) park with a swimming pool complex near the top (and IIRC still a museum on Hong Kong history) and a smaller part with a big wall across the main road. In Central, I see runners along the water beyond convention center, including around some yacht harbor. Other spots for outdoor exercise would be around the big Buddha (very crowded on weekends) and the peak.

I'd strongly suggest familiarizing yourself with the basics of Hong Kong culture and etiquette before leaving. Little things can be noticed, like always handing someone your business card or credit card (pretty much throughout Asia) with two hands and looking carefully at any business cards that are handed to you before putting them away with reverence (not just shoved into a pocket mindlessly) as a treasured item that you'll keep.

I think I agree with the advice to stay at the same hotel as your colleagues and get those five Starriott nights elsewhere on weekends or whatever before NYE. Splurge on a stay in the center, go to Macau, or stay in a Starriott near the airport on your last night in Hong Kong for the first trip, which seems to include only one weekend in Asia, so you might need to do a couple Starriott nights in the USA too, perhaps using an airport hotel before or after your long flights.