I think your OH-12 analysis is pretty off, Badger.
Franklin County is roughly 50% of the district, while the other 50% is made up of other counties. And would-be Freedom caucus member was only narrowly behind Balderson in terms of fundraising. Between Balderson, Bacon, O’Brien — and maybe even Kane — there seems a very good chance Leneghan becomes the nominee for not only the special but the general too.
This is also the most winnable special election yet. I started off feeling very negative about this, but am feeling pretty confident now. OH-12 has a very active Indivisible, too.
Also, this is not John Russell’s first run for office. He ran for state representative last year in the district that is comprised of East Delaware County and all of Knox. He lost, obviously, but outran Clinton by at least 7% in every precinct, and upward of 20% in other areas.
I didn't realize half of the electorate was in Franklin County. That does change my view somewhat, though if I recall correctly at some of the more Republican areas such as Westerville.
I'm not saying the freedom caucus nut can't win the primary. Though I'd be interested in knowing if her fundraising numbers included the $200,000 gift from the freedom caucus. That would indicate if she has some Grassroots support as well. At any rate, if she wins this is at least toss up if not tilt d.
Wait a minute. Are there two elections going on, one primary for the special and one for the general election? 
As Oryxslayer pointed out, it looks like I misremembered. Franklin is 25% of the district, though, which is a strong plurality. The municipalities include Columbus -- notably greater Clintonville area, which is among the most activist segments of the city -- Dublin, Gahanna, New Albany, Westerville, and Worthington. Trump massively underperformed both Tiberi and Portman in all these areas.
In the OH-12 portion of Columbus, Trump got 31.26%, Portman got 44.51%, and Tiberi got 49.06%.
In Dublin, Trump got 46.24%, Portman got 64.97%, and Tiberi got 69.69%.
In Gahanna, Trump got 42.00%, Portman got 55.87%, and Tiberi got 62.60%.
In New Albany, Trump got 49.18%, Portman got 65.74%, and Tiberi got 62.60%.
In Westerville, Trump got 45.19%, Portman got 59.24%, and Tiberi got 66.46%.
And finally, in Worthington, Trump got 31.47%, Portman got 47.48%, and Tiberi got 52.31%.
In the entirety of the Franklin County portion of OH-12, Trump got 37.13%, Portman got 51.73%, and Tiberi got 56.82%. In the entirety of OH-12, Trump got 53.20%, Portman got 61.92%, and Tiberi got 66.34%.
Balderson's a better general election candidate, but he's still a #BulldTheWall #MAGA Republican, and that' not playing in Franklin County, nor Delaware County, and the tradeoff of bumping turnout in Muskingum isn't enough. I still think John Russell is a better candidate than O'Connor, especially since he ran at least +7% ahead of Clinton in the more conservative parts of Delaware, but given the national mood and the grassroots strength in Delaware and Franklin Counties -- which together, make up +45% of the district -- I think this is definitely in play no matter what happens. Even Scott, who would have trouble in Franklin County -- and Clintonville in particular -- would still do okay, and might even win since he'd actually play fairly well in Mansfield and Zanesville.
I definitely agree with X that Jay Goyal's decision to skip out on this election was a huge mistake. He won't ever have another come back opportunity like this again, and it'd have been very cool to have two Indian-Americans representing Ohio in Congress.
And yes, the primary for the general and the special is on the same day. Kasich did the same thing in OH-08 in 2016. (Related: J.D. Winteregg, who attempted to primary Boehner in '14 and ran the infamous "Electile Dysfunction" ad, is now running for the state legislature.)
