These cruisers were really a pair of mini-battleships - We Are The Mighty

Not really. Battle Cruisers like the HMS Hood had battleship-caliber main battery (15"), but sacrificed some of the armor of a battleship to give it the speed of a cruiser. The Alaska Class did not have a battleship-caliber main battery, but a unique 12" intermediate size half-way between a heavy cruiser's 8" and a battleship's 16". The Alaska class would be more closely compared to the German Admiral Graf Spee, armed with 11" main battery that the British coined a "pocket battleship", as compared to the Bismarck's 15" main battery.

IIRC the Arizona had a main battery of 12 inch. I think the North Carolina had 14 inch.

LTC Gene Moser - North Carolinas: BB-26 (1910) had 12 Inch main armament, BB-47 was to have 16 inch but was scrapped in 1923 before completion and BB-55 (1941) had 16 inch main armament. Although, BB-55 I beleive was originally designed to have twelve 14 inch but the 1926 naval treaty allowed it to be changed to nine 16 inch.

Odd that 12" guns were chosen for this class of warship when by this time the only US Dreadnought that still had 12-inchers was USS Arkansas. Would 14" have been better since there were still a number of battleships already in service with this caliber?

Ahh, the mighty Vreeland FF1068. Too bad it's a Knox class frigate