One interesting question is what the "who's who of the Street Fighter canon" would be at this time. I've gone to my strategy guides and the Street Fighter canon plot guide, and using 1968 as a point of reference for the campaign, here's what I've come up with.
First, we only have birth dates for the core 15 characters (minus Lord Vega) from the SFII era of games and for wrestlers from Muscle Bomber. In 1968, most of the main Street Fighter characters are young children or haven't been born yet (Ryu, born in 1964, is 4 years old). But there are a few who are nearing fighting age, especially considering how early fighters seem to get into the game in Street Fighter.
The year is 1968. Zangief is 12 years old. The man who will eventually come to dominate the fighting circuit, Sagat, is 13 years old. Dhalsim is 16. Mike Haggar is 27. Oro is already a hermit in Brazil and is currently 108 (born 1860).
These ages are definite. What else do we know? Well, the Japanese strategy guides estimate Gouki's age in SSFII Turbo as around 48, which would put him at around 21-23 in 1968. Gouken would be roughly the same age.
We can extrapolate other ages from there.
Here are some canonical characters who would probably be of or near fighting age in 1968.
- Gen (based on his age in SF Zero, he'd be 50-60 years old in 1968)
- Go Hibiki (Dan is roughly the same age as Ryu, which would suggest that Go Hibiki should be old enough to have a young son. Go could easily be about the same age as Gouki and Gouken -- in his early 20s.)
- Zeku, Bushin-ryu Master (roughly the same age as Gouki and Gouken?)
- Retsu (same as Gouki and Gouken?)
- Li (a little younger --maybe 16, Dhalsim's age)
- Kanzuki Juro (Karin's father, he'd work well at around 18-20 -- Karin is born 1973)
- Rolento (he's late 30s to early 40s in SF Zero, which would put him around 20 in 1968)
- Chun Li's father (Chun Li is born in 1968, so her father could be in his early 20s)
- Remy's father (13-18)
- Belgar (end boss in Final Fight -- maybe around 21-23)
In addition, there's Lord Vega, who I mentioned before. His age is unknown. If he's around the same age as Chun Li's father, he'd be in his early 20s -- the same generation as Gouki and Gouken.
And then there are a few teachers from Rival Schools who might be young fighters in this era.
I'm not sure if Goutetsu would be dead yet, or not. Ryu doesn't come to train with Gouken until he's around 8 to 10 years old (again, roughly), which wouldbe around 1972-74. I think Goutetsu is dead before Ryu comes to train with Gouken. So either Goutetsu would be dead when the campaign started... or the clock would be ticking.
Some of this info is based on the Japanese strategy guides and Gamest Mooks I have laying around here. Some is based on The Street Fighter Canon Plot Guide (v4.6). Much of it is basically guesswork and creative interpretation.