Some of these are more utterances than real words, but they all appear in the dictionary, so: What one-syllable words are vowel-less and do not contain an A, E, I, O, U or Y?
#2 & #3 are Welsh words - Welsh has many words without the 6 letters. And the third does not necessarily have a lake - it is a circular depression on a mountainside caused by glacial erosion, which may now be dry.