The most important thing to determine is if the Roland DJ-808 is USB class compliant. I did a quick search and couldn’t easily find an answer to that question. If it’s not class complaint you will not be able to MIDI map it. If it is, you should be fine. MIDI mapping in djay is quite straight forward. You might however run into issues getting the level meters working properly as this can be a challenge with djay’s MIDI editor.
As for the drum machine, I have no idea.
DJ 808 is not class compliant unfortunately. Last update was in 2018 so I doubt it will ever come. It’s a great controller though and sounds amazing.
Roland is weird about which or their products have class compliant drivers which I assume is to get you to buy more of their stuff. For example, their flagship $800/$400 drum machines in the TR8/6s do not have them. But their new entry level $200 products in the T8 drum machine/bass synth, J6 chord synth and V4 vocal effector do and also act as audio interfaces.