I also advise building it up, Mr. Tree first, then Jevin, then Gray, then Fun Bot, then simon, then whoever you want on 6 slot, ones that I've tried being Vineria, Durple, and as you can see in the image, Black, then wenda either before or after the 6 slot. (also off topic but the non horror designs kinda remind me of Pou)(2nd edit: Sky is one of the best ones for slot 6)