I did a little research and this is what I found.
Your Indian is 1916.
The rear leaf spring was introduced in 1913.
The handlebar crossbar was first used in 1914.
The rear of the front fender is flaired, that started in 1916.
The motor is a 61 cubic inch V-twin.
I could tell more if I could see the other side of the motorcycle.
The sidecar is not Indian brand, the front curve of the nose is verticle. All indian sidecars had a horizontal bend.
I tried to add the info to your web site, No luck
Thanks for asking
A Century of Motorcycling