Hi Mark & Team,
I don't know if this is even possible

the reason I've been asking for Custom Field ACL instead of Privacy is because Privacy is managed by Users whereas ACL is managed by Site Admin, I guess

at least to my understanding.
I am building a Lock Down mode community, so all Users will have to Login to see everything. In Advanced Search Select Field, I would like to limit the ability of Community Users by letting them search for Name, Email, Gender only (initially). But I would like the Staff Group (Joomla Group) or Staff Profile (ES Profile Type) to have all the fields as criteria for Advanced Search. That way we can collect demographic data as Management but limit the Users to just basic Search functionality.
The issue with the current (v1.2.17) setting in Custom Field is if Search is disabled, even the Site Admin doesn't see the Field in Advanced Search select fields dropdown. It's like on or off, I also posted a question about this
here.
Thanks,
Jackson