In table top, warlock slots are separate from other spell slots, but you can still use any spell slot to cast any type of spell you know. This is one reason why warlock + Paladin is a very popular power build.
Well, no hexblade here, and we don't know what pact of the blade looks like yet, so in order to do that multiclass is may have to be Warlock 3/ Paladin X, which is a huge pain with respect to getting the extra attack on time.
