The letters [r,w,h] conventionally refer to "consonants", specifically, non-syllabic segments, whereas [r̩,u] refer to syllabic segments ("vowels"). Similarly, [j] is a consonant, [i] is a vowel – but [j,i] are the same except for that difference (and also, [m,n] are non-syllabic, [m̩,n̩] are syllabic). [h] is a bit of a problem because it has no unique syllabic variant that can be articulated on its own, nut in a sequence like [ha, hi], [h] is phonetically a voiceless version of the following sonorant segment, so you could transcribe "ha" as [ḁa], "hi" as [j̥i].
The terms "consonants" and "vowel" are confusing since they are used in multiple ways. Sometimes, "consonant" vs "vowel" refers to syllable structure pattern, in which case [h,r,j,s,l,p...] are "consonants" and [a,r̩,i,l̩] are "vowels" (usually nobody calls [l̩] a vowel but [r̩] is often called a vowel, in English). But if you are talking about the decree of constriction in a sound, then the terminology changes. This is recognized in some theories of phonological features sucha s the SPE theory, where "consonantal" refers to a particular degree of constriction and "syllabic" refers to syllable-structure function. So [h,j,w] are non-consonantal, but non-syllabic; [a,i,u] are non-consonantal and syllabic; [m,l,p,s] are consonantal and non-syllabic; finally, [m̩,n̩,l̩] are sonsonantal and syllabic. The standard definition of "consonantal" is "a segment with more mid-sagittal constriction that that of [j]".
Versions of r add one other complication. American English r is generally an approximant [ɹ] and not [r], and it is non-consonantal which can be syllabic or not. In other languages like Serbian, Croatian and Sanskrit, there is a syllabic version of [r], thus [r̩].