I did a little dig on Vincent Fusca. I was surprised how many articles came up that featured a prominent photo of him, always with the hat, glasses, longish hair and scruffy face.
http://www.ncregister.com/daily-news/catholic-concerns-about-u.s.-climate-change-policy
https://www.ydr.com/videos/news/local/2016/07/18/87267208/
I think this might be his linkedin. It seems to fit.
https://www.linkedin.com/in/vincent-fusca-a9b14a99/
https://fox5sandiego.com/2017/06/03/march-for-truth-calls-for-independent-probe-of-trumps-alleged-russia-ties/
http://www.post-gazette.com/local/south/2018/03/06/Saccone-rallies-with-miners-in-Waynesburg/stories/201803050180
http://www.nydailynews.com/news/politics/trump-fans-gather-pittsburgh-not-paris-rally-article-1.3218328
https://www.pagop.org/about/counties/allegheny-county/
https://www.gettyimages.ae/detail/news-photo/vincent-fusca-places-a-campaign-sign-on-his-truck-for-news-photo/927762074
There's also a Twitter account that seems to be him (pics related). If it really is JFK Jr, this twitter account is some EPIC master trolling.