The question is two-part I suppose.....
Firstly, does each sequential service pack for 2016 contain all of the relevant data that any other preceding 2016 service pack had? In other words, can you just install SP3 and bypass SP1 and SP2 because SP3 has those earlier two versions worth of data plus more. Or, do you have to do them all?
Secondly, can the service packs be downloaded as .zip files so that they can be saved to external hard-drive and then installed on a workstation(s) that are not connected to the internet or intranet?