Well, I don't the lyrics of that song, but if the singer says "favorito" that's because the adjective must refer to a noun of the masculine gender. Favorito is masculine and favorita is feminine.
tienda just does not sound like it would be store. I want to say "time" or "season" whenever I see this word.
Maybe you can associate it with "tent" then associate "tent" with "shop" (store) ;).
Soy el comandante Sheppard y esta es mi tienda favorita en la Ciudadela
The correct spelling of favourite in English is favourite. Favorite is a lazy American English spelling.
This really isnt the place to rant about language or spelling dialect differneces. You can point out a difference without being judgemental or disrespectful.
[ o / ou · favor / favour ] · [ favourite · US favorite · Origin - Late 16th century (as a noun): from obsolete French favorit, from Italian favorito, past participle of favorire ‘to favour’, from Latin favor (see favour) · favourite ]
[ · From Middle English favour, favor, faver, from Anglo-Norman favour, from mainland Old French favor, from Latin favor (“good will; kindness; partiality”), from faveō (“to be kind to”). Respelled in American English to more closely match its Latin etymon. Compare also Danish favør (“favor”), Irish fabhar (“favor”), from the same Romance source. · favor · ]