I saw Migros is selling a one day SBB travel card for 2 people for 54 CHF. valid on trains, buses and boats anywhere in CH.

http://www.migros.ch/DE/Aktuelle_Angebote/Gruesse_aus_der_Schweiz/Seiten/SBB_Duo_Tageskarte.aspx

As I am planning to go the Luzern to see the Mount Pilatus. Does anyone know if this Migros pass is also valid on the Pilatus train, Cable cars, and Gondola?

I would assume there are no further restrictions to the Day-pass ie it has the same validity as a normal SBB day pass. So check out:

SBB - 1 Day Pass - information

Follow the Link for the validity overview map and I think it shows the Pilatusbahn on there too...