Mongwe to Vic Falls is not an easy option and the simple answer to your question is no. You could take a Charter flight out of the valley as they regularly fly into Mana and back to Vic Falls but that is not going to be cheap.
Even if you were able to get to Kariba there are still no scheduled flights to Vic Falls. You would need to get back to Harare first to catch any commercially scheduled flights. the same with public transport you will need to go via Harare and getting back to Harare is difficult unless you go back with your family transport. Another option is the Kariba ferry but you need to get to Kariba and then at the other end from Mlibizi to Vic Falls, Transfers for that can end can be arranged though.