I would not risk it without a B2B and appropriate cabling/fusing. If your van has a smart alternator how is the voltage/charge rate going to be controlled?
If you want to maximise the life of your lithium battery, alternator, charger, control unit and cabling, install properly with a B2B etc so you are presenting the battery with correct voltage/charge and let the BMS be a last resort protection.
Sorry, to me, I think its marketing bovine effluent to "drop in replace"
(I have two LiFePo4's and LOVE them. We very rarely have EHU. I would not go back to lead-acid so I am a huge fan of LiFePo4 ....... but this "drop in" nonsense .......)