Looks good.
As for who Plantagenent would marry, since Anjou and Normandy were traditional enemies he might go with a wife who could net him support against Normandy. The obvious candidates would be someone from Brittany (Normandy's other traditional enemy), Scotland (England's traditional enemy), or Champagne (The major Frankish territory a this time, ruled over by Stephen's family).
I doublechecked my sources and it turns out you were right. The Anglo-Norman barons only opposed the marriage when it became clear that Matilda would be Henry's heiress, hoping they could get her to marry one of their own.Not quite true there, jmberry. William III is already married to Isabella of Anjou, sister of the orginal plantegenat. Henry I liked Gregory at first, and much of their disagreements came at his forced marriage to Maud. I doubt he does anything here to draw England's ire.