According to Wikipedia, the maple leaf as a symbol of Canada dates back to about 1700. Other symbols could be a buffalo, beaver or moose maybe?Canada...
Three gold fleur-de-lis were the Bourbons' symbol IIRC. How about a blue stripe on white for either the Mississippi or Gulf of Mexico?New Orleans...
British Columbia's setting sun could be used for Columbia's position on the west coast. Also possibly a beaver, or a douglas fire (from Oregon and Cascadia respectively). Similar to OTL CoA of Canada, the CoA could be England, Scotland, Spain (a Burgundian cross?), Russia (black eagle on yellow).Columbia...
If the people of New Russia didn't really want to be independent, then the flag would probably be quite similar to Russia's.New Russia...
Something to do with the number 3 and/or 4 for the 3 major islands (Cuba, Hispaniola, Puerto Rico) and 4 countries etc. (Cuba, Haiti, Dominican Republic, Puerto Rico)?Greater Cuba..
How these suggestions help!