Mosfets are based on Input voltage of SCC ~ 45 V for an open circuit and selection is from whats is readily available here in the market.
If you have something specific in mind, please share but availability becomes an issue generally.
1) 75V, 130A is IRF1407 -> Rds On 7.8mOhms Rja-> 62 °C/W With that I think it should be able to deliver 30-40% of its Amp capacity which should be about 40Amps (Just my guess). Doubling the Mosfets as pair for redundancy and Load distribution.
2) 200V, 30A is IRFP250N -> Rds On 75mOhms Rja-> 40 °C/W This one again with higher IR but lower Rja should be able to deliver around 30%. So would need to put 4 of these to make upto 40A output.
The IRFP250 has a very high Rdson, it would dissipate 67.5 W at 30 A, so yeah, not a good fit.
The IRF1407 is much more reasonable at 7 W but it'll need a decent heatsink. Even with 2 of them they're dissipating 1.8 W each so their Tj will be at 162 °C (for 50 °C ambient) without a heatsink which is far too high, given the low power even a small heatsink would do but you need one.
You would need 3 of them (4 or more is highly recommended) to be able to go without heatsinking (but don't put your fingers on them, they'll still run hot...).
Now for the driver instead of a BJT I am now considering a small logic level Mosfet which should be easily driven with 5V input and no additional resistance (Ideal for a micro controller based triggers). The one I checked is 2N7000. Its Id max (Drain current) is 200mA - which might not be sufficient for the big Mosfets to overcome gate charge quickly, but since there's almost negligible switching required it might do the job in its own time - remains to be seen. This also solves the Issues of common ground or negative - which should be common with BMS/Battery's negative terminal in my opinion.
That doesn't solve the isolation problem. What I'd recommend, as switching time is not really a big deal here, is a very simple and easy solution: a small isolated DC/DC converter with a 5 V input and 9 to 12 V output. For example:
https://www.mouser.fr/ProductDetail/RECOM-Power/ROE-0512S?qs=wlO1EFRhkBBs39O4z6CwKg== or
https://www.mouser.fr/ProductDetail/Cincon/EC1SA02N?qs=a9HUcNGsM2BlT21ZHg8YSQ== or
https://www.mouser.fr/ProductDetail/MEAN-WELL/SPU01L-12?qs=5aG0NVq1C4xapU/W8eQMIw==
In addition to that you just need to add a resistor (a few k should be good) between the gate and source (which is the same as saying across the DC/DC converter output) to be sure the mosfets are turned off when they should. And as the converter have a roughly 40 mA no load input current that's too much for a MCU I/O so the 2N7000 is welcome here.
Also, even if not strictly necessary, I would recommend a small (4.7 µF - 10 µF) capacitor on the input of the DC/DC converter. And I would also recommend adding a resistor in series with each mosfet gate.
That's a 4 components solution for the drive circuitry, I don't think we can do better than that
Here's a schematic (I used some IRF540 as I didn't had the IRF1407 in my libraries but you get the idea):