Multiple member ID's for family

Hello

We have brother and sister scouts with multiple id’s and advancements not showing up.

Sister: Old MID is 136213104, new (current council) is 1383940, but they put the old one in scoutbook so advancements would show up. Can these now be merged and have the current council primary without advancement being lost?

Brother: Old MID is 12926688 (West LA), also 129166882?
Current Council MID 13819029 (Greater Los Angeles), but also dual with Ship in Long Beach (don’t know the MID). Would like to merge, but not sure if they paid primary with Long Beach or GLAAC.
Want to get the MID’s settled since he wants to transfer Troops within GLAAC.

Will need to make sure mother is linked to them both, not sure if she also has multiple MIDs, but suspect so. She

Any assistance, advice would help.