Migration - dolphin Connect particular problem

No question of bugs here, but of a particular problem.
As Andrew said, and after much thought, I agree with him, the best way to smoothly migrate from a dolphin site to UNA is to work with two parallel sites and bridge with dolphin Connect.
But I know my members and have spent a lot of energy on getting them to complete their profile 100%.
To fix this problem, I changed Dolphin Connect to get all the fields from the profiles on my dolphin site, even the fields linked to predefined lists work and it's wonderful.
The only problem I encounter is the following.
I have 16 fields in total, it is a little much to complete for a new registration, so the unimportant fields I disabled them in fields => people => Add Persons. Nice.
Thus new members can join us quickly, and then all the fields appear when they want to complete later, and so its activated in fields => people => Edit Persons. Nice
So far so good !
The only problem I have is that Dolphin Connect refuses to import ALL fields that are disabled in fields => people => Add Persons.
I know Alex, you're going to tell me he's not made for that. Still, there is only one solution, it is absolutely out of the question to lose this information during the trip.
So I hope your brain has a solution to work around this problem, otherwise I'm desperate.
If you have a solution, then you will make sure that I can sleep peacefully, it has been months since this problem prevents me.
Please, tell me you have one! ;-)