Some of it is typical Trump stuff, but Vander Plaats doesn't have clean hands. Santorum and Romney can tell you all about how much an endorsement costs. (Romney refused to pay, so it went to Huckabee that year.)
I know that Santorum has met privately with Trump on a number of occasions, I suspect that Rick had filled in Trump on this topic.
I don't know about anyone else, but I am tired of these operatives that merge Religion into Politics/Government as a business. I am hoping that more of it gets exposed throughout this election season. It has no place in the politics or government of this nation, and needs to be excised out. YMMV.
Vander Plaats actually endorsed Cruz fairly quietly back in mid-December. Trump started his Twitter rant on it last week as just another politic tactic for Iowa. Jacobs claims that Peoples has confirmed Trump's fee, but I've never seen it publicly documented other than her article and Tweets.
Many will be poring through the FEC filings to track disbursements to "Family Leader" this cycle. And the beat goes on....