I don't have experience with any of your nutes except the GH ones. I've used maxiBloom alone all the way through, following the lucas method
guidelines. I use Liquid and Dry koolBloom but the one you have there is the dry ripening formula which is for the final week of feeding, to be followed by your flush.
I start using the liquid koolBloom about a week after flowering gets going and ramp it up over a couple of weeks but that brings up the P and K. I usually dial back a bit once i see the tips of my leaves start to dry/burn. JUST A LITTLE BIT. Big Bud is a 'bloom booster' and I believe it competes directly with liquidKool bloom so you should be able to use that the same way.
This is what my slightly burned tips look like:
Bud Candy is a sugar/amino acid additive. Looks to be similar to FloraNectar from GH. It's not a nute per se although may have some mineral values. You should be able to use this in conjunction with the rest of your stuff.
Advanced Nutrients is one of those brands that really knows how to market well and make lots of money. They will make their products sound exceptional and magical and promise you the moon for the extra $$$ you pay for it. They'll also encourage you to use more of it in their feeding charts than most plants can tolerate so start small and learn to read your plants and ramp up safely. You don't want to go and hit it with 100% max feed strength by the recommendation and have to immediately deal with a deficiency.
Lastly, you referenced that you're on week 6 since sprout. Growth cycles aren't exact. 6 weeks doesn't necessarily mean anything except that if they've been healthy (and they do look good) then you should be starting to see preflowers. My Blueberry plants never show preflowers before flipping the lighting. I think you're safe to flip to 12/12 by the looks of your girls. The 12 hours of dark are the important ones to kick it into flower. Once you start seeing lots of bud sites showing up, then you can start with your bud booster.
I am still leaning myself, but I don't think I've dropped anything misleading here. I hope this helps.