The cut line only applies after that round is played. If you put it at par for the first round, everyone who shoots par or better will be eligible for the next round, and so forth.
I don't know, but maybe a cutline on the final round knocks players out of the money if they don't make it?
Not necessary. Only players playing all rounds - in other words, not WDing - get into the money.
Here lies a danger of cuts: If nobody reaches or finishes the last round, any credits at stake are collected by WGT. There was such a case a few years ago.
Therefore, don't force too harsh cut rules - they might kill the tournament!
OTOH, I don't see any use in cuts here. There is no crunching of participants necessary, and those who are bad from the start will stay low in the leaderboard, unless they quit by themselves.
BTW: One extraordinary example of quitting NOT happened in the Club Championship of a real German golf club about 10 years ago:
Preliminary note: Those Club Championships have multiple (2 or 3) rounds, and the competition is genuine stroke play, not Stableford. So players will be DQed when a score on one hole is missing. They won't be able to play the further rounds.
On a hole with a demanding pond in front of the tee, a participant, in the first round, carded a 63 => for one hole!! (1) He must have putted along the bridge across the pond after drowning a few balls, eager to stay in the game for the second day! (2)
BTW: He then added a 10 and 4x11 to his scorecard...
BTW2: He played an 8 on that hole on the second day.
(1) I've seen the official scorecard via the Golf Union's website. Checked and confirmed today. The distance from the tee is 130 m to the opposite bank,
150 m to the FW.
(2) This is my interpretation.