They just posted the Jan hours on the App. Both parks 9am-9pm, early entry at Islands. I would do your full day at your preferred park (sounds like Islands) and the half day at the other park. For the busy time of year and such limited time, I probably wouldn't bother with park-to-park tickets.
Any of the onsite hotels will give you early entry, and the 3 premier hotels would also net you unlimited Express Passes (though those hotels will be pretty pricey that week). The buses & boats from the hotels are very efficient no matter which hotel you pick. Normally packages don't save you much, so you can pick & choose the hotel/tickets you prefer.
Do be aware that Popeyes raft ride & Dudley Dooright log flume will get you legit soaked. Jurassic Park River Adventure will get you spritzed to somewhat splashed, but not anywhere near the drenching of the other two.
If you want to do Hagrids first thing, you are probably looking at being to the gate 45min+ before the 8am early entry. If you are not near the front of Early Entry, don't go for Hagrids in the morning. Normally the Hagrids line wanes around lunchtime or mid-afternoon, or you can hop in line shortly before park close. Early Entry not-right-at-the-front works nicely for Forbidden Journey, Velocicoaster, and checking out Hogsmeade with lower crowds.
If you want to eat table service meals in CityWalk, particularly around park close or popular dinner/lunch times, it would be a good idea to make a reservation. The menus & prices are posted online. CityWalk is literally right outside the parks, so don't feel like you need to stay in the parks for lunch.