Words that contain 'pn' and end in 'a'

Is there a word on this page that jumps out as the most common?
There's 'pneumonia', which is the 40839^th most popular word.

What is the max number of words one can construct using words that have 'pn' in and end with 'a'?
On this list of words that have 'pn' in and end with 'a', you have 77 outstanding entries which are available.

Is there an example word from this page which could be thought of as unique?
A good example of a weird word from this page goes to 'orthopnoea'. According to the Oxford dictionary, 'orthopnoea' is defined as "Specifically, a morbid condition in which respiration can be performed only in an erect posture; by extension, any difficulty of breathing.".

In Scrabble, what's the most points possible from words containing 'pn' and ending with 'a'?
You can make 'hypopnea' which scores 18 points.

How many letters does the largest word from this list contain?
'Pneumonocarcinoma' is the biggest word that we could construct. It consists of 17 characters.