I put him in a pair of wrestling "shorts". These were typically worn with tights (but not always) and probably more of a 20th century thing, but I was loathe to put him in period-appropriate underwear.
I'm limiting his clothing to items he wears on the covers of Tip Top Weekly (one of the first nickel weeklies to go full color on the "wraps" ~ a big deal in 1896). Also, I am limiting his wardrobe (aside from the shorts) to items depicted between 1896 and 1900 in order to keep him within the scope of this blog. So expect to see some very early sports uniforms (some might even surprise you), and other "Gay '90s" apparel.
Lastly, I used the logo from the weekly as his name on the base of the doll. Issues were titled "Frank Merriwell's [something or other]; or, (and then an alternate, more descriptive title)". So I adopted that format for the titles of these blog posts.
When I have posted all the pieces, I will "plate" these for easy print-quality downloading. In the meantime, click on the images for larger versions and enjoy!