I recall the late 80s - Brian Stowell was Mr Manx - he seemed to run every class with maybe another 20 or so especially around Peel helping - I guess there are probably now about 250 truly competent Manx speakers (I'm guessing somewhat based on the number required to teach, handle the translations etc - one sees the same names always cropping up here) but there will be more entering secondary education from the St John's school who will no doubt wish to build up their knowledge and the vocabulary will obviously expand - already one sees a considerable number of new publications, especailly to cater for young leaners, rather than the manxified version of material taken from Irish teaching sources. You are right re the political context as Mec Vannin had it as one thing they pushed.
Manx music is flourishing and new life has been breathed into the folksongs - the Whitehouse at Peel seems to be the centre for much of this but there is now enough interest to sustain a week long annual festival of dance and song.