It depends on the lease you acquired. If it can be migrated to Coretime, it will. Then your lease will be served regularly and your DOT get unlocked once it expires - just as before Coretime. Once it expires you will have renewal right on Coretime.
Leases that will be refunded, are ones that only start after Coretime launches. E.g. if you acquired a lease that would start in August, but Coretime launches in June, then your future lease will be cancelled and you get your DOT back immediately.
Well, now the LAOS auction is taking place and I want to participate in it. But sending it for two years is too risky in terms of reasonableness. It suits me if I send them to the lock now and they will be returned to me at the start or after the start of CoreTime.