Hi VarunGrazitti ,
just to clarify a few points regarding the subject.
Regarding the custom field, at the moment this can be added via Li Professional services only,
--- if there is no on-going projects with PS, Support could be happy to assist you in this subject.
and that is at no additional cost
--- it is really case by case basis. In general, one-time setup and zero customization would be at no cost or low cost.
They will set it up on your staging instance for review and then once you confirm, will be pushed live in your maintenance window.
-- when the fields are added to stage server only, not production server, the studio publish will be disabled. most of the time, we will add to both stage and production at the same time.
<the custom profile fields> “will also be available in the metrics reports.”
--- it is not OOTB or by default, you need to explicitly tell Lithium that you want to include those fields in your user report.