I've seen LCC play a couple of times this year and I think what you are saying is the part that's hardest to prep for ... stopping/limiting the big play.
LCC's kick return hasn't been all that good this season, although it has been consistent. Up until the Rochester game, LCC's longest kick return was 26 yards. Against Rochester, they pulled a 71-yarder. Similarly, LCC pulls a couple one- or two-play drives that are big in either sparking the team or taking the wind out of an opponent. Outside of the 3A teams that LCC faced this year, Guerin, West Lafayette, and Heights, they've been able to hit those big plays as well as just standard movement ... Metzger tends to be 100 plus rating when not playing 3A opponents.
I like LCC's odds on the passing side of things if Metzger's on. Comparing to the LaVille passing opponents:
Bremen - QB rating of 100.4 with completion rate of 56.5% ... not including the second loss to LaVille. Scored a TD roughly every 6.7 completions. Roughly 2,190 yards on 11 games.
Glenn - QB rating of 60.4 with completion rate of 50.2% ... not including the loss to LaVille. Scored a TD roughly every 9.5 completions. Roughly 1,150 yards on 11 games.
Andrean - QB rating of 88.5 with a completion rate of roughly 56%. Scored a TD roughly every 11.5 completions. Roughly 1,700 yards on 10 games.
Metzger's comparison is QB rating of roughly 108 with completion rate of 50.2% not including second Seeger game. Scored a TD roughly every 6.9 completions. Roughly 2,540 yards on 11 games. Four receivers with 300 or more yards a game and a total of over a dozen targets for the season.
If LaVille can shut down the pass, then that puts LCC in a bind ... although most teams think about shutting down the pass being with their secondary and LCC's really good at exploiting LB coverage and screens, so the linebackers need to be very in tune to the passing game. If, as @First_Backer_Inside mentioned, LaVille may not have the offense, it could be an issue of how many big plays LCC musters; even if LaVille can impede the passing.
Incidentally, I give LCC the intangibles. As @Donnie Baker says, that west endzone at LaRocca is good for an 8-point advantage and LCC will have played three of four tournament games at LaRocca come Friday night. The field should be in really nice condition for a grass field ... and the LCC receivers will be quite aware of the parts that give and the parts that don't.