Here are the possible solutions for they could be this puzzle's theme clue
Answer
Clue
Relevancy
races
Clue
They could be this puzzle's theme
Definition
RACE, to compete in a contest of speed
four
Clue
Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
Definition
the cardinal number next above three
badhairday
Clue
What any of this puzzle's theme entries could cause
inn
Clue
Place that could fit this puzzle's theme
Definition
to stay at a public lodging house
info
Clue
Theme word inside this puzzle's theme words
Definition
(short for) information
lllllllllllllllllllll
Clue
Much of the Smurfs' theme song, and this puzzle's theme
rawhide
Clue
Classic TV theme song covered by this puzzle's theme duo
Definition
to beat with a type of whip
skewedtooneside
Clue
Like this puzzle's theme, to solvers concerned with puzzle symmetry?