What is the ruling on a Sunni person eating with, sitting with, and socializing with innovators (Mubtadi'ah) at work, and is it permissible to marry a Sunni girl to him, and is it obligatory to inform her of his socializing with them?

Interacting with non-Muslims at work and during meals is permissible according to Islamic law, as long as there is no forbidden act (munkar) or call to innovations (bid'ah). However, one must isolate themselves from them if there is a forbidden act that cannot be changed, or if there is a fear of being influenced by them, for "a person is upon the religion of his intimate friend." As for informing a fiancée about the suitor's condition, it is permissible if she consults you or if you advise her to marry him, so that they can ascertain that he is not influenced by people of innovation and immorality. This is because many scholars prohibit marrying an immoral person, and some scholars have even gone as far as prohibiting marrying an immoral person from the outset.