Strictly speaking the only canon is the KC game and the kanmusu voice lines.
Most people take the KC anime as base for canon, but, for example, there is an abyssal [not ashamed] difference between Anime!Kongo with her zany antics, and the voice lines KC!kongo uses in the game; the "dess" schtick so notably attached to her in the anime is non existant in the game, or the fact that her "grope line" (usually the Secretary line 3) is actually a rebuttal stating something along the lines that "it's not the time or place". Anime!Kongo would go absolutely bonkers if her Teitoku touched her, appropriately or not.
You can check the
KanColle Wiki for all the shipgirls' voice lines, and in some cases the wiki provides personality traits about a few of the girls, like Jintsuu being extremely shy. Problem with that is that you have to go to each individual shipgirl page, so if you intend to use a lot of shipgirls you end up spending quite some time checking voice lines.
Also, obviously, if you intend to use non-Japanese shipgirls, there are a few of them in game and with voice lines, most of them Italian and German. They recently added a few Allied Shipgirls, like Warspite, Iowa or Commandant Teste, but there are very few. So you will have to make up any non-Japanese shipgirl you want to use. As the KC fanfictions have started to pick up on popularity, some fanfics are used for a baseline personality for common shipgirls.
In some cases, that personality may clash, even. For example, there is a very similar concept universe, called the Sea Queens, where ships have a personification, but have no control over the ships. There is also a Kancolle fanfic called Belated Battleships (BelaBatt). In that fanfic, New Jersey is portrayed with a similar, but considerably toned down version of SeaQueens!Iowa. Jersey's personality is more detailed, though, because SQ has a very few snippets portraying Iowa, while BelaBatt is quite a long fanfic which has fleshed more Jersey's personality.
Using, for example, the characterizations from BelaBatt, or KanColle:Greatest Generation, allows you to "acquire" a reader base more familiar with the character, but you are also constrained by the defined characterization, and people may complain if you stray too much from the "canon" fanfic characterization, even if it's your own story.