As you can see in these two replays, Shell Bell activates before switching out due to Red Card. Per the Bulbapedia wiki, "The Red Card switches out the attacker before its own held Life Orb or Shell Bell has a chance to activate." (so the way Red Card interacts with Life Orb is also probably affected!)
https://replay.pokemonshowdown.com/gen8doublesou-1441038151-w0989yl4fnw1p0xgts3uq9qdn92zlz1pw https://replay.pokemonshowdown.com/gen8ou-1441038726-4f78s8oai7gj21cn35o2ejwm1ckvg97pw
As you can see in these two replays, Shell Bell activates before switching out due to Red Card. Per the Bulbapedia wiki, "The Red Card switches out the attacker before its own held Life Orb or Shell Bell has a chance to activate." (so the way Red Card interacts with Life Orb is also probably affected!)
https://bulbapedia.bulbagarden.net/wiki/Red_Card