For anyone interested in what's inside the Kona battery these photos from DIYelectricCar.com provide a few insights - although mostly confirmation of what we already know. The short thread is here and mentions how the original BMS is used, quite an accomplishment IMO. Notably, it appears that the BMS can be replaced via the access opening many of us have seen on the underside. I've marked some of the module cooling connections with yellow arrows along with other major parts. The coolant flows through passages under the modules so is not quite as effective as Tesla's Betty Crocker-style construction whose coolant channels pass against a portion of every cylindrical cell's wall and is completely encased in a non-serviceable cast foam. The coolant ports through the housing wall have been repurposed for wiring so it appears that the cooling system is not required for the scope of this project. It's not clear if this is a recalled battery or an accident-salvaged part. What I've marked as a possible automatic disconnect looks very much like a thermal fuse, due to the vents. I've broken the photo into two halves to try and improve the forum's resolution.
Using the existing BMS may be a big load of programming work, but it allows using the existing pack almost intact - saving a lot of manual labor! And programming a BMS controller is a one-time effort, so it can be easily replicated on other packs.
The best site where I found that we can see pack's internals. https://pajalle-com.translate.goog/en/2022/02/02/konan-akkua-tutkimassa/?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp Maybe it will help you out.
The "automatic disconnect" might be a pyrotechnic fuse - a small explosive charge designed to immediately - and very completely - sever the electrical connection in the event of an emergency, such as a severe collision. I don't know of Hyundai uses them, but it's in the right spot for it.
The Tesla S Performance has them on two of the motor connections. If recall correctly the understood intention is to allow the motor to freewheel in case of a controller failure.