Does a 24 word seed phrase fully cover the entire "address space" such that if all combinations of seed words are used, all possible wallet addresses will be mapped / addressed?
That's a complicated question. I suspect the answer is probably yes because of all the redundancy, but there is no guarantee. However, I am not an expert.
BIP 32 describes how private keys are derived from the seed.
BIP 39 describes how the seed is derived from the seed phrase (and optional "passphrase").