Massive Creations Upside Down Cake LSO x2 & Big Pond Genetics - (First Ascent) Unicorn Poop X Mendo Montage x2

Hey guys! I am very excited to show you my second attempt at indoor cultivation. I have decided to only grow in living soil from now on and will use only organic fertilizers and methods. I am currently praying that most of these plants are female, the seed distributor I bought from only had regular seed packs for the strain I wanted. I bought a Massive Creations 10 pack of regular Upside Down Cake seeds. I got 2 free Big Pond Genetics First Ascent (Unicorn Poop X Mendo Montage) regular seeds. I do not know of a way to for sure tell if they are all female or not, though one of the 4 plants is growing much faster and larger lately. I am in week 6 of vegetative growth and will be flipping in the next few days if not tonight. The 15 gallon pot will not require additional fertilizer because of its size and the living soil I am using (Adonis Living Soil). For the 3x 3 gallon pots I will be using organic water soluble complete nutrients. I am thinking that I should use some organic bloom fertilizer in the next few days so that its available during heavy flower. Please give me any advice or tips as I am still new. Is there any way to tell if I have females before flip?