When Conservative is spelled with a capital C it usually refers to the Conservative and Unionist Party of Great Britain. Spelled with a small c, it becomes the adjective conservative meaning *averse to change or innovation and holding traditional values. People, in Britain at any rate will sometimes describe themselves as 'conservative with a small c'.
Similarly Catholic, spelled with a capital C usually refers to the Roman Catholic church, and/or its members. But spelled with a small c, it means: a wide variety of things; all embracing. So I may describe my taste in food as catholic meaning I am willing to try anything.
But whilst I have heard plenty of people describe their tastes as 'catholic', I have never heard anyone use the expression catholic with a small c.
Would it generally be understood and accepted into mainstream conversation if someone did. If not, what is the term, meaning 'all embracing', (apart, of course from 'all embracing').