I feel like I remember some of that stuff coming out in the spring or early summer. I know I had some of it during the summer as I spent the summer out of the state and bought some of it while I was away.
April 1989. I looked it up in Dragon Magazine (#144). DMG came out one month later, and MC a month after that.
As an aside, the 1E PHB was kept in print one year after the 2E was released.
http://www.acaeum.com/ddindexes/setpages/phb.html