Welcome to WS's!
What else could she have done? It seems from what we do know, he was employed by the newspaper, he was the delivery guy back then, he did try to contact someone at least in 2016 and again in 2020. We can't say for certain that he didn't contact them in 2005 because now KZ is saying it was possibly withheld, resulting in a Brady violation, or should at least be looked at by the courts to determine if it was.
She includes a request she made previously for logs/recordings and was told "we do not have recordings for that time period". So he's not believable because they didn't keep the recordings? That seems awfully convenient, IMO.
As for his statements and being different, I can see where there are slight differences, but nothing earth shattering. I don't think it makes a difference what night he saw this, but it could make a difference that he saw it at all. In his first email, he doesn't say he didn't know who it was (but does give a description, maybe he didn't want to put that he thought it was Bobby in that email?), he did say it was not Brendan though. Asking for a name/phone number is different than providing one IMO IF the officer or call taker was dismissive to the info he was providing, I can see a situation where he says, hey, don't you want my phone number and name? (thus not being asked).
Saying that this information was 'useless' in 2005 is just as dismissive as he said the officer that answered the phone was. There are times when something that appears not relevant, is actually very relevant, and seeing two men pushing a vehicle in the middle of the night would not be 'useless' in this situation IMO Not when a young lady has lost her life and her vehicle fits the description. Strang/Buting deny seeing the email in 2016, so they didn't just 'dismiss' it.
IIRC Calumet county didn't take over until the day the RAV4 was found, or it was decided that MTSO wouldn't be the lead investigators, but this didn't preclude them from taking phone calls from the public about the case.
Considering he was on that property every night delivering the paper, it seems to me that he should have been interviewed anyway... but wasn't. Maybe he saw a fire? Maybe he saw something suspicious? Maybe he smelled something?
And one last thing... why push the vehicle? Sound would be my #1 reason. JMO