Chichi. The fact that she's stood by him throughout all the things he's done in their lives, not even moving on in those 7 years he was dead and determined not to come back, says a lot about how satisfying their relationship was to her. They also work well as a couple as shown by their ability to compromise with each other and how their opposing elements create balance when it comes to raising their children. Bulma might have proven better in a utilitarian sense of having no problem with Gohan being raised as a fighter and having access to a gravity chamber should Goku ever want it, though it'd definitely lead to their child becoming quite spoilt as we saw with the present version of Trunks.
As for the other choices, all we have to go off on Blue Lunch's abilities is that she's kind and likes to cook, which isn't much in terms of relationship material (especially when she's not as good a cook as Chichi) and Suno is pretty much just a blank slate. Caulifla would be the worst choice for Goku as, whilst they'd have good compatibility with each other, she's definitely falling short in the child care category, not to mention we don't even know how old she is with how diminutive in stature the U6 Saiyans are.