Yes, Congress does have to approve them, but the pick is done by the President, and in this case it would be Harris. Your original post said this...........................
You hinted that Congress would pick Pence as VP since there would be a 50/50 split. No, Congress doesn't pick who Harris would want as VP, Harris would pick them, and then Congress would confirm them. They can't confirm someone that they pick themselves, they have to confirm (or disapprove) someone that Harris picks as her VP. And, while it may have happened in the past that a couple of presidents haven't had a VP, that is one of the reasons the 25th was created, so that problem wouldn't happen. And yeah, it would be political suicide for the GOP to try to leave the VP position open. Not only would the Dems campaign on how the GOP was trying to harm our system of government, but it would also encourage other nations to assassinate Harris, as it would leave a vacancy in leadership. Besides, if Harris did take over as President, the GOP left the VP slot blank, and then some other country had her assassinated, you DO realize who would become President then right? Pelosi. According to the rules, if the Pres. and VP are taken out, the Speaker becomes Pres. Do you really want that?