Nice choice of fish .... this is the pair I had.... the male (larger one) killed off two of his competitors.... then they spawned.... raised some fry... then he killed his wife..... beautiful fish but can be unpredictable.... (typical cichlid)...... only had them in a 2x15x15 tank ... going to try them again some day in my sumped system with 3x18x18 tanks where my shellies are....
Hope yours do the right thing and get the step breeding going ..... might need a larger tank for that though....
yes, as prevoiusly mentioned... the scientific names are correct in most cases with some wholesalers but you are starting with some common, common names and some that are dubious to ID the fish - your LFS or others who have access to their price list will have the actual names :)
Be careful of lifting names off wholesaler's websites - there are a few "americanisms" and incorrect names floating around in your list above... and Betta unimaculata is actually 'commonly' known as the Gold Dragon Betta - only unnamed Betta species go by their collection point alone - most will have their species name followed by a collection point if in fact this is known (most imported into Australia are not known). I would post a link if I was allowed to but....
Roy - Betta pi = arithmatic Betta due to the Greek symbol pi on their chins - the elephant Betta term is not that common name for them
Also remember these names are invented to sell the fish to people who don't have any clue about correct naming of species - these common names also get made up by collectors and sellers to sell fish that seem to be something new - such as I announced a new line of wild type Striped Dragon Bettas (aka B. patoti)
My advice - use the true name of each species - you will be more likely to get fish that are real and not just some mixed batch of fish named to sell to people who don't know betta :)
@ Yan - wasn't worried about what you ordered at all - wholesalers get things wrong all the time - was simply pointing out that:
B. strohi is the Blue Ninja Betta and B. foerschi is the Ninja Betta
@matsay-raksita - lack of blue iridescence on any fish bought as B antuta could mean they are too young as you suggested (although they will colour up well before full size is reached). It could also be that they are female - generally its only the males in the unimaculata group that have the blue colouring. The chance of them being misnamed is always a possibility when purchased through a non-specialist source (ref to Yan's comments above about ordering one species and getting a different similar species supplied).
@Adam - yes... NINJA Betta is B foerschi and the BLUE NINJA Betta is B strohi