So now we have a conflict – either women used to wear really long robes in the desert so sandals were allowed OR they wore sandals but had their skirts above their ankles? Hmm..which one is it?
Broch, with all due respect, wearing a long skirt below your ankles is allowed by many rabbonim. Rabbi Falk may have clearly defined that in his sefer (I never read it), but it doesn’t mean it is universal. In fact, if you start looking back in the sources, ervah and shok are highly debated as to where it is – including areas like the upper arm possibly allowed to be shown! Most people don’t pasken that way, but not everyone paskens that way about long skirts either!
Shaatra, most people I know hold that wearing socks is a minhag hamakom.
I am not certain about the ankles, but I was taught its ok to keep them uncovered. My sister does not hold by that. I would ask your LOR for details.