You should be able to get your luggage moved to any of the Disney owned resorts. However, there are no guarantees that your new room will be ready before normal check-in time, although I was able to check in around noon once. If there is anything (like bathing suits) you may want before this time, keep them with you. Also, your luggage will not be delivered until the afternoon.
If you are on a meal plan you will not be able to continue it. The new reservation is a totally new reservation and you would have to buy another park ticket if you were signing up for another meal plan.
I have done split stays and loved them. I send my luggage on ahead and then go to a park. In the late afternoon I head over to the new resort and I can get the room and have my luggage delivered (it does not get automatically delivered to your room).