I think you are right to be a little concerned. Ordinarily the chances of a non-holiday February weekend day filling up right when Reservations open up, would be slim. But with Rise Of The Resistance opening, it could complicate things. If it's available, I'd probably book Saturday first, and then the next day, Friday. Saturdays "usually" fill up first. My guess is that you will be o.k., but you should be able to get a good idea for when Reservations open in December for the 1st weekends ROTR is scheduled to be open. If those 1st Saturdays fill up right away, then you may need to be concerned. Theoretically CA Adventure should not be impacted by the ROTR mania, so hopefully you could get a reservation there, even if DL was unavailable.