Generally, there is little to object to Tepan’s corrections.
I would say just ‘poka mi’ rather than ‘lon poka mi’ but that is dialectic within pu (Sonja has supported both expressions).
coffee is variously ‘telo wawa’.’telo pimeja’ or ‘telo pimeja wawa, etc. (also ‘telo pi lape ala’)
There is nothing about commas on pp 51-2, or anywhere else in pu. People have all sorts of habits with commas but none are “official” (remember, nothing inn. tp is official as there is no governing body). Sonja, in pu, regularly uses a comma before ‘la’ after a sentence and not otherwise, but when describing the structure, she omits the comma. Commas are never *needed* with ‘la’ (any more than with ‘li’ or ‘e’), but are occasionally useful (as they are elsewhere) to block wrongheaded parses. (And they naturally go after the ‘la’ -- but that is just opinion with no grounds for either view).
The bit about ‘o’ goes to page 41, where Sonja manages to do the right thing while totally muddying the previous decade of usage. She says 'jan o pali’ is to express wishes or desires, an optative, in short “Would that the man acted” or some such. But this pattern already is used in tp for a fusion of a vocative and imperative: a short form of ‘jan o, o pali’ (that is one comma that does seem to be required, though there is no rule about it). All of the eamples given are either clearly or most likely cases of this sort, not optatives at all. The old optative form is to put ‘o’ in front of a declarative sentence ‘o jan li pali’, but this is unmentioned.
On the positive side, I think what you want is an imperative with ‘mi mute’ as the audience (hortatory imperative) “Let’s get together and drink coffee” ‘mi mute o kulupu li moku e telo pimeja'