Will publisher waive fee if currently unaffiliated?
This surely depends on the journal, and probably on your specific case (I don't imagine it's common to have a blanket waiver for authors without affiliation).    Many journals do provide support to authors without funding.  For instance, look at the PLOS FAQ #4: 

https://www.plos.org/publications/publication-fees/


  Publication Fee Assistance is intended for authors who demonstrate financial need. [...] PLOS considers applications on a case-by-case basis. 


Try looking at the webpages for journals you're considering for such information.  If you can't find anything, you can try contacting the journal.