I was thinking of two R5 IIs, one R5 and one R7 for September as the environment is risky to gear and cost is very high. If not available, I'll only get one. Sometimes only 2-3 bodies is fine. For example, if cost is high, but risk is low, then I'd choose three bodies. If cost is low and risk is low then two bodies are usually fine, such as for landscapes. We don't know yet if the R5 II will be any better than the R5 at ISO 100 where ECFS is normally used.
The R5 is pretty good on birds, but sucky on mammals. Several of the controls and modes of the R5 are archaic compared to even the cheaper new bodies. There is also the stupidity of the new flash shoe, which makes the R5 shoe unusable in the future. It's better to have multiples of the same model so that you pick up one and it is the same as the other. Ideally you don't want one model body on a 500 or 600/4 and another on the 100-500 for example as it's easier to miss something. I've used multiple same bodies such as the 1Ds II, 1Ds III, 5D III, 1Dx, etc. There were several years when I used the 5D IV and 5DsR together, but often with a replicate of one or the other as a third body. In recent years I've done crazy stuff like using an R5 w/100-500 and an a7r5 with 200-600 together, but it's quite a pain.