Well lithium is a tough pill to swallow for a hobbyist learning system. Unless someone has a really good source, will have to hold off on those until they become more commonly available.
Right now, I can go to any parts store, walmart, and SHTF scenario, thousands of cars to get a replacement battery. Finding lithium close to me will be a challenge even without any happenings in the world.
Still thinking about 2 banks, 1 running battery. 2 banks bump up to 400 ah per set (6x the walmart 24ms sized marine). Combined with a running battery, should be up around 900 ah. Trying to build in a "2 is 1" mentality within the system, so that if solar or wind charge controller takes a crap, the damage will be limited to that particular side.
Fridge estimated to take about 1900 watts a day, and the 600w solar best I can find produces about 3000w per good sunny day, wind is pretty good here but could be a few days without, so those few days are going to need the extra capacity to run freezer as well as fridge. It just may not handle both loads considering the losses from inefficiencies. But if grid goes down in the winter, refrigeration can be moved to the garage and will take much less power. Or just get a 12v charging system hooked up to a small engine and use it to charge system when it's dreary and still outside.
70 amp diodes seem to be very common, running battery will draw from whatever bank is doing better at that particular time, and should both drain evenly when not producing.
My concern with hooking both charge controllers to the same bank is when one is putting out 14 some odd volts, the other controller is going to see that voltage and dump the power thinking the battery is full, instead of putting all the amps it can into the depleted battery. I'm far from an expert on the subject and maybe that's overthinking it. But I also fear one of the controllers taking a crap and dumping overvoltage into the batteries which would limit damage to only half the bank if they're split up.
When the roof is replaced we'll likely get a big boy solar system with lithium storage. 5 years timeframe. Want something quick and working should something happen before then. We still have gennys and even a diesel pickup hooked up with extra RV batteries and inverter as a last option.