I hope Bayern do what we did last year when we lost to Napoli after celebrating the league win to much.
They won't.
You remarked in the match today that they had the Wednesday match in mind, it was for sure no great match, but they won 1:0 - and yes - they celebrated a little after the match and maybe will drink a glass of champagne or a beer on the way back to Munich - but I doubt that there will be more. They will really celebrate the title on May 11th when they get the trophy - in a home match. If the championship would be more of a surprise - but the only question that was open was on which date they will win it with only a point in need because of a 34 better goal difference to Dortmund.
Heynckes did not really play a B-team today. Mandzukic stayed in Munich and Gomez played - not really a B-version - and Shaqiri started instead of Ribery. But he e.g. let Müller play 63 minutes to get him accustomed to the position again - he only played the CAM-position twice this season until last Tuesday and all other matches on the right wing. And he let Ribery come in for Robben after 63 minutes.
Müller was fouled in the penalty area - but Alaba missed the penalty. Two other penalties - one for Gomez and one for Frankfurt was not given. The match was won by a Schweinsteiger goal assisted by Lahm.