It will be impossible to defend bases with 24h invite cooldown and no cave building
One of them is possible, if you have no cave building but also no invite cooldown, it works out and you can actually defend your base.
If you have cave building but 24h cooldown, you can also defend your base because you can hold most caves against a much larger group of attackers
But no cave building and 24h building cooldown has never been done before for a good reason, because it simply doesnt work.