Yeah I agree on Little Tough Guys probably never coming out. It is the least know of all the series so that would make it even less a priority. I don't think the series has ever been released on TV. I've never seen any of them except for a bad VHS of Little Tough Guy.
I think the 3 serials are considered part of the Little Tough Guys series as they were made by Universal at the same time the series was running. Which also explains Leo Gorcey's absence as he was heading the East Side Kids series at Monogram and Billy Hallop was heading the Little Tough Guys series at Universal with Huntz Hall crossing over both series.
Nearly all of the Dead End Kids Features have had proper DVD Releases, with the inaugural DEAD END having been issued by MGM, and the rest by Warner, except for THEY MADE ME A CRIMINAL (I don't count LITTLE TOUGH GUY (1938), as Leo Gorcey isn't in this, and thus could be counted as a defacto Little Tough Guys inaugural entry!) which is apparently a Public Domain Title, at least judging by the number of Studios that have issued this. The three later Dead End Kids Serials, JUNIOR G-MEN (1940), SEA RAIDERS (Though minus Leo Gorcey, I question the Dead End Kids Moniker. More of a defacto Little Tough Guys, in my opinion!) and JUNIOR G-MEN OF THE AIR (1942), were released to DVD by a less than stellar name (Alpha). All of these can be currently found on Amazon at reasonably obtainable prices. In my opinion, the one series that has very little chance of ever seeing proper issue is Little Tough Guys, as I don't see this one having any kind of priority with Universal, who I presume holds the Release rights to those films.