You can include the (free) Advanced Custom Fields plugin within a free or premium theme/plugin.
You can include your (premium) purchased Add-ons within a premium theme/plugin as long as it is made clear in the copyright / information that the Add-ons are not to be used or distributed outside of the premium theme/plugin.
You must remove the update script from each Add-on to prevent distribution of updates. Instructions are included in the Add-on readme.txt file
You can not include (premium) purchased Add-ons within a free theme/plugin.