actually he is Bart, Wally and Barry rolled in one if you think about it just like How Wally in Superman The Animated Series, Justice League/Jlu is an amalgamtaion of Barry
(Wally is a forensic scientist, which was Barry's profession instead of an auto mechanic like in the comics, the only existing Flash in the series, he was never Kid Flash (although in the episode "Flash and Substance", a Kid Flash costume is briefly seen on display in the Flash museum). He lives in Central City, Barry Allen's hometown as opposed to Keystone City, Wally West's hometown. He is a police scientist, which was Barry Allen's job in the comics. His origin is also that of Barry Allen's. This Flash also fought some of Barry Allen's enemies throughout the series, such as Captain Cold, Mirror Master, Captain Boomerang, Gorilla Grodd, and The Trickster. Wally also has the Flash ring, which was invented by Barry Allen in the comics, to store his Flash costume in.) and Wally (
he has red hair and green eyes like Wally does in the comics. This Flash also has Wally's girl-crazed, occasionally big-headed manner, paired with a childlike attitude and intelligence. When he tries to vibrate his molecules through solid objects, he causes them to explode as opposed to passing through the object intangible like Barry Allen would. He also has a good relationship with Hawkgirl) or Barry Allen on The Batman(Creators stated that their version was intended to be Barry Allen but acted like Bart).
Smallville Bart had
Barry Allen elements:
-founding members of the Justice League,
-He has nearly the same age as Clark, only a little younger, where Barry and Clark are around the same age
-there doesn't seem to be any other speedsters other than Jay Garrick, leaving Bart to be the second superhero speedster, just like how Barry Allen is the second Flash
-Bart's
Smallville explanation on how he got his powers is much more in line with Barry and Wally's origin instead of his own,
-In his first appearance, Bart's hair color is blonde and short, similar to Barry Allen's hair in the comics and how John Wesley Shipp who portrayed Barry Allen on the TV series
The Flash.
-In Toyman's files, Bart is listed as being a Central City native, as well as having blonde hair, blue eyes and the ability to pass through solid objects, similar to Barry in the comic books.
-In his first appearance, Bart at first goes at the same speed as Clark but is revealed to be much faster than him. In
The Flash: Rebirth, Barry is shown as being much faster than Superman, easily outstripping him as Superman tries to keep up with him. He claims that those times that the races between them were tied were "for charity".
Wally West elements:
-Wally's girl-crazed(way Bart acts around Chloe), occasionally big-headed manner, paired with a childlike attitude and intelligence
-Wally had to eat vast quantities of food to maintain his metabolism.
-Wally had a falling out with parents and got struck by lightning and got his powers
and
Bart Allen elements:
- Bart goes by the name Bart Allen, rather than Barry.
- His personality is similar to Bart when he was Impulse
- In his later appearances, Bart's hair is brown and long, similar to Bart Allen's hair.
- Bart's JLA codename is
Impulse, the first identity of Bart Allen
even though the Producers, writers, episodes description and that one scene in Stilleto called him "the Flash" was forced to refer to him as Impulse later due to a DC request.
so Young Superman is correct in saying that, Smallville Bart is an combination of those 3 Flashes sorry for the long post.