That's a really tough decision you have in front of you. It seems like you realize that it may be an uphill battle (maybe a losing one). Your step one definitely isn't helping, but you have a solid step 2. A year of research and the personal connections gained will certainly be of benefit to your application but they are not a guarantee of interviews. I don't know your situation but, consider where your potential mentor's connections are. If he is a graduate of a big name program and a big name fellowship, it may not matter how much he recommends you to their residency/program director. It MAY get you an interview, but it would be unlikely that you would shine so bright that you would be ranked higher than the multitude of 250+ steps/AOA/promised donation to school/etc... applicants. If you choose to follow your passion, you might be better served by applying primarily to community programs, with a few less prestigious university programs.
It is very much a personal decision whether or not you are willing to work unpaid (although, paid research positions are available) for the chance to follow your dream. You can always double apply GS/Ortho next year. It may just delay the inevitable by one year, but at least you gave it a shot??? Although, to play devil's advocate, delaying GS match this year probably won't help your GS chances in the match next year, as a year off may be a red flag to programs... Good luck with your decision.