Breeding pet lvl

Genetic multi, Breeding multi, Rarity multi and more ,i havent unlocked all the boosts yet, all boost the new pet chsnce. But do they also effect the min/max pet level/power? Or what does determine the power level of pets you hatch?

Also what is the best place to Afk for splicing each world? I hear people say shorter afk times for more splicing material but is this true? And if yes, why?