They could also slap on a Choice Band for Lucario and have it learn Ice Punch instead of Swords Dance but I prefer facing the SD version instead in all honesty. Her Garchomp could have a Choice Band or Life Orb though haha.
Regarding Garchomp, that thing makes me cringe just thinking about it. I recall facing it with a Hippowdon roughly around level 67 back in Diamond and I nearly got OHKO by a non critical Dragon Rush, that literally made me sweat due to how hard that hit even something as bulky as a Hippowdon of all things. Thank god I never sent up my Salamence or Empoleon against it ugh.
Only kind of moveset I can think for Spiritomb is Swagger, Psych Up, Sucker Punch, and either Shadow Sneak, Embargo, or Taunt but yeah it's fine being left alone for the most part anyways.