i feel like approaching with the mentality of 'straight until proven otherwise' in regards to characters like john & jane & roxy is kind of eeeeeh but i guess its whatever you want to believe. wouldn't agree with calling their straightness 'canon' though, as its never confirmed.
There’s canon evidence behind John and Jane being straight tho and yes they could grow and figure out that they weren’t but based on the evidence presented, canonically they’re likely straight
But, here’s the main point I really want to get across: