I'm gonna have to re-watch this episode, cause it will drive me nuts. As for the park - he mentions to Lorne that there is a park across the street from his house where lots of kids play, and his Jeep was parked across the street from his place, parallel to the park. I could've sworn he was just loading his Jeep when he heard Justine come up, and not actually heading into the park.
As for the the two meetings with Holtz, I browsed through transcripts of those scenes, and Holtz does mention "wanting the baby to live", "the baby not being safe with a demon", and so on, but I didn't see any discussion of Holtz taking the baby. Even though Wes met with him twice, I still never really saw them as great allies, and think that even though Holtz confirmed what Wes read in the prophecy - he still thought Holtz was a madman driven by vengance. I also think that Holtz knew ,deep down, he didn't have a chance of getting Connor away from Angel. From there, I believe he thought his only option was to manipulate Wes(playing on the fears he already had) into taking the baby - and I think that's where he thought he would see his opportunity.
Is it mentioned anywhere else?