Hey regarding the shellos, the only flawless calm seed in gen 4 unfortunately carries ability 0(Sticky hold). Just want to make sure you don't want a Pentflawless(with storm drain) before I RNG it.
EDIT: Yet another issue, the only useable seeds that have shellos in an encounter slot where NPC's are controllable are these:
30/12/30/30/30/31(HP Flying 68)
31/7/31/30/30/31(HP Ground 70)
30/10/31/31/30/31(HP Ghost 70)
30/5/30/30/31/31(HP Grass 68)
31/17/31/31/30/31(HP Steel 68)
The other option is a 31/26/31/31/31/31 Gastrodon, but you specified Shellos so I want your choice.