After integration of IPB and MOS with amember, will future upgrades of IPB and MOS be difficult? Thanks
Not at all! aMember only works with scripts databases, integration doesn't require any changes to MOS or IPB source.
It is impossible to move them directly. It is only possible to import to aMember first, then ask your customers to login into aMember once. Then encrypted passwords will be de-crypted and you will be able to move members to IPB database.