Trying to make a bike an authentic tribute is a neat thing, but beyond my patience and budget. I love the board track racers, but I also like a lot of the early motorcycles which were not know for racing. They were bikes that got ridden as very cool transportation by regular people, so there were practical concessions like lights and brakes, even.
A couple of years ago I saw a photo Fasteddy sent me of an Indian tri-car and I fell in love I decided then that I wanted to do a tribute of a 1909 or so and started out with a Worksman Newsboy frame. As soon as I started considering what to use as a power plant the compromises began. I saw an Indian engine not even running on ebay listed for eight thousand which was about eight thousand dollars more than I could afford. So, you start making compromises and have to come to terms with reality.
You can do something that suggests one of the old classics and some here have done builds that are amazing in quality and at first glance fool you into thinking its the real deal, a Flying Merkel or whatever. That level of commitment, skill and investment is way beyond me. Same for most of us. So it is a matter of how closely one tries to go to the original inspiration.
Some do very little and yet call their builds board trackers. Flipping the handlebars on a cantilever framed Huffy with an Indian decal does not an Indian make in my estimation, although a person is free to do whatever they want. What I came to as a guiding principle is doing a build "in the spirit of". And I broadened my inspiration to early motorcycles of the early teens into the 1930's which left me a lot of leeway in choosing to go my own direction and use what I wanted that appealed to me as being "in the spirit of" an early tri-car. I call it an Indian Hiawatha even though there never was such a critter. It does have an Indian headbadge, 1939 Hiawatha fenders and a fender ornament that says "Hiawatha", and the engine is vintage, a 1934 Fitchel & Sachs 2 speed motorcycle engine. The headlight is from a who knows early German motorcycle... and so on. There is no particular historical machine it looks like, yet it does look pretty authentic as an old time motorcycle which is fine with me. I like it and I'm the one who needs to be pleased.
So what I'm suggesting is to free yourself up some and do things "in the spirit of" to give yourself some breathing room and allow innovation and changes in direction along the way in your build. It seems pretty clear that you have serious intent, are willing to be patient and are putting a lot of yourself into this build. It is going to be yours, unique and will turn heads. And someday it may get passed down to a son or daughter as a part of your family history. "My dad built that" will mean more than "it's supposed to look like a such and such year Indian". You're the one who's going to ride it. So long as it rings your bells, all is good.
Silverbear