EE will be an easier major change at UCI than UCSD (extremely difficult as Undeclared) but there are no guarantees for spots at UCI either.
http://www.changeofmajor.uci.edu/CoM_Engr.html
Are your parents willing to spend $60K/year to attend UCI with the chance you may not get into your preferred major? Did you get your FA package from all the schools?
If your parents can pay the OOS costs, I would lean towards the direct admit at UC Davis or your Florida schools. As long as the schools EE program is ABET accredited, you will get a good education at any of the schools listed.