Words that contain 'n' and end in 'tas'

Which word from this list contains the highest number of letters?
'Subplacentas' is the longest word that our database could find, containing 12 letters

What's the highest number of points you could get in Scrabble from this list of words that have 'n' in and end with 'tas'?
One can make 'juventas' which gets 18 points in Scrabble.

Which word that has 'n' in and ends with 'tas' is the most common word?
There's 'sonatas', which is the 69781^st most common word.

In total, how many words are possible to make using this list?
On this page of words containing 'n' and ending with 'tas', there are 33 entries which can be selected.