I wouldn't make transplant as auto doesn't like that. The bigger the hole you dig and put a better soil, the better the root system development at the beginning, and so on. If I were you I would dig the biggest hole I could to fill with the maximum soil i got.
Pests depends a lot from the place you live, and where they will be. Neem oil is perfect to turn your plant and soil around unpleasant to all pests. You could also put eggshells around the base so slugs wont go there.
I would grow them on rockwool, or jiffy pellets for 15 days, them put on soil.
Wish you a great grow!