I agree with PureGro that the object on the green at CB #12 is a sprinkler head.
I believe the 2 people behind PB #5 are WGT photographers
OK, it appears you are one for two here...
It is a ball marker, not a sprinkler head, but the 2 people behind PB #5 may, in fact, be WGT photographers.
I sent the question, as to identification, up to the suits and this was the "Official" response from WGT:
Jan 30, 2022, 5:32 PM CST
My money would be on these being people photographing/mapping the course. I know they close down the areas of the course to photograph/map the course, so I would doubt these being players because of that.
WGT Member Services
I would like to point out, this would mean that some of the hidden objects may not have been created by WGT, intentionally. Most of what we see, golf carts, ball markers, etc were there at the time that WGT mapped the courses.
So, considering the ball marker was 70' away, somebody actually had to mark their ball, astonishing!
Furthermore, consider the possibility that Bigfoot and the Easter Bunny, as well as the eggs, existed when the course was mapped. Even more, visit PureGro1 before considering it, and it is easy to accept this theory.