How to migrate 12.1 non-cdb database to a new server (EXACC) converting it to multitenent?

Since doc 2386116.1 advises that non-cdb is no longer supported on exacc for 12c ( I can´t convert to cdb before it goes to exadata), I´ll not be able to use dataguard strategy and the convert to pdb after migrate it, due image for 12c are only availble as  multitent. Not sure if rman inc  backup  would work since the source is non-cdb and destination db must be a pdb,  goldengate is out of the

question since it involes additional license. I´m still learning about the mutitenent architecture, so forgive me If I missing some detail here.

This db has a really heavy load of processing and it´s critical 24x7 enviroment, so leaving the database in read only for a long time is a big issue.