As is clear from the photos the Atlantic figures are very small, looking more like 13 year old boys playing police than actual adult cops. The Atlantic set had a police dog and a motorcycle. Two figures that the Red Box set is missing and would have made nice additions. The German Shepherd and Bloodhound have been staples of American law enforcement for 100 years.
For some reason the Atlantic figures have a field phone or radio. Not sure why this was needed for police.
The motorcycle cop from Atlantic is firing or at least waving his pistol. Not generally the best way to ride your bike. These two sets are very different and are unlikely to be usable together. The Red Box are very clearly American, mostly for the interwar period and the Atlantic are very clearly European, mostly post-WWII. The Atlantic are very small in comparison to the Red Box, both shorter and much thinner.