[flat.map.capacity]: Where are the other `flat_meow`'s correspondences about this?

Only flat_map has an additional [flat.map.capacity] to specify the implementation of size/max_size member:

size_type size() const noexcept;
-1- Returns: c.keys.size().

size_type max_size() const noexcept;
-2- Returns: min<size_type>(c.keys.max_size(), c.values.max_size()).

However, flat_multimap, flat_set, and flat_multiset have no corresponding sections. Where does this inconsistency come from?

In addition, since all flat_meows are adaptors containing the underlying container, I can't understand why their empty/size/max_size/clear are all noexcept. According to the Lakos Rule, they should not be declared noexcept because the implementation should be by calling the member functions of the underlying container, and these functions are not guaranteed to be noexcept.
(I believe the standard seems to pay great attention to complying with the Lakos Rule, this is also reflected in the non-noexcept empty/size of the stack/queue).

Not quite sure what I'm missing with the above.

Start by comparing the [flat.map.capacity] wording for flat_map with the corresponding flat_multimap, flat_set, and flat_multiset sections, then review their empty, size, max_size, and clear declarations. Check the cited stack/queue declarations and the Lakos Rule discussion for the noexcept rationale. Done means the inconsistency and noexcept behavior are explained and any needed draft wording is identified.