More recently, Puss-in-Boots appeared in the movie Shrek 3, and rumor has it that he may soon star in his own film.

What does more recently indicate? Is it sooner in time than recently?
Second, I wonder why it's rumor has it instead of rumors have it since there is no doubt more than just one rumor. Could you dig up a reason as for why?
Hi Angliholic

'More recently' refers to something which has happened more recently than something that was mentioned previously.

'Rumor has it' is a fixed expression that refers to one rumor -- a story or fact which people are currently claiming is true. In this case, the one rumor is that Puss-in-Boots may soon star in his own film.
Dear Angi,
Rumor has it that.. is an idiom, a colloquial expression.
All in all, idioms usually don't make much sense to the listener's ear. Emotion: smile
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 Yankee's reply was promoted to an answer.
Got it! Thanks, WA and Yankee, for your time and reply.