@Tamerlane They're likely all meant to be straight. This sort of thing is a very Japanese trope that plays off of a normal concept there of almost-romantic-level friendship which doesn't really exist in the west anymore (It used to be a thing back in like 18th-19th century times and shows up often in classic English literature from that era). Almost always the characters are never meant to be gay/bi/whatever, it's just expected that especially with school-age girls there will be friendships so close so as to seem like romatic/sexual interest, even to the point of playing it up for comedy purposes by making one a perverted creepy yandere stalker type often because it lets them get away with saucy gags in a way that would be viewed far more negatively if the aggressor was a guy.
https://tvtropes.org/pmwiki/pmwiki.php/Main/RomanticTwoGirlFriendship