Ededn CXC210 Combo

[Mutation]

I suppose this is for the Edenites out there but i have recently purchased second hand but perfect condition and Eden Time Traveler Combo CXC210 which consists of a front ported 210 cab with a WT330 head built in.
I have a couple of questions regarding it. It seems from my investigations that the internal speakers constitute a 8Ohm load which should only draw 200w out of the amp. Even so it seems that this wattage well exceeds the ability of the 2 x 10" speakers to handle so I want to add an additional cabinet either a E410XST or E210XST to make use of the available power.
My questions are

Which is the better cab choice? 410 / 210 / 4Ohm / 8 Ohm?

When adding cabinets of different resistance do all cabinets draw power from the amp according to their OHM rating ?

If the internal speakers start breaking up at say 40% on the master volume having additional speakers connected will be louder no doubt but i presume i wont be able to turn it up any further

Any help, hints, insights or suggestions appreciated!