The match of The Shield vs Evolution that WWE seems to be teasing for Extreme Rules was supposedly planned even before WrestleMania 30, reports The Observer Newsletter. And while the possibility of that six-man match seems very possible at this point, Ric Flair is not scheduled to get involved in the Evolution reunion.
The pairing of Triple H, Batista and Randy Orton will likely be temporary, and is primarily being done to help put over The Shield, so it makes sense that Flair wouldn't be used in this case.
Future Plans For Andre The Giant Memorial
It appears the 'Andre The Giant Memorial Battle Royal' will indeed be returning next year. Although things can always change between now and WrestleMania 31, The Observer reports that WWE's current plan is to make the battle royal a regular match and attraction at future WrestleMania events.
Many wondered whether WWE would use the match at WM 30 as a stepping stone for the superstar who won it, and it's clear they plan to do that with Cesaro. Furthermore, it was unclear whether or not the gimmick match itself would be used again in the future, but this report suggests it will.