The answers all depends upon your end goals and what you are starting out with in the first place. Are these hives in double deeps, are they well stocked with reserve honey at the moment, is your flow still on, etc. Splitting hives can be done from packages, i've done it myself, but I made sure to feed both the split and the donor colony after doing so. I used already mated queens for my splits as well so they could take off quickly.
Decide what you have to work with and verify it. Then decide what it is you really want from your bees, more colonies, less varroa, etc. Then make the plunge from there. Also it may be notable that I started with 3 lb package bees myself.. And have had two queen losses since then that i've had to make my own queens for...