I buy my coconut and palm oils in 19 kg quantities. When I get it I unwrap it (it's usually a giant cube that's been pressure sealed) and dump it into a large plastic tote with a lid. I keep it covered and scoop it out as I need it. I had my first load in the totes for 8 months and they never went rancid. I still have some of my first soaps I made with it too and they don't have DOS, so I'm thinking that's an okay way to store it.
As for the liquid oils, I don't buy them in large quantities because in my case, I can actually get them cheaper at the grocery store! So, I never have them sitting around for long. I buy a couple of bottles of each, make up a bunch of bases and use them up in about a week.
I think as long as you are using your liquid oils up fairly quickly you don't need to worry about refridgerating them. The only time I would think they'd go bad is if you had them sitting around for a very long time. I think in your case, with it being so hot where you live, and the fact that you'll be opening them regularly, I would probably put them in the fridge just to be safe.
