love hearing the words accented in the correct way makes a refreshing change .nice and soft sound without the yeshivish incorrect Hebrew that hardens the musical fluency.
I think the Shovuos one is probably the least well known, possibly because there are only two days of Shovuos and these days you always want to do one day as the Saqui Yigdal in addition to the 'Blue Book Trads' - so the kehillah think they have got something they know! However, you will hear this one you've featured here if you're where I am this Sukkos!
That is very possible! My experience is I have heard the Shavuot Yigdal in person very occasionally, but never the Sukkot one, at least not as done here. Saqui seems to be the default for Sukkot. But this definitely varies from community to community. Certainly the Pesach melody is the best known of the three.