3. Klein vs. Knipex?
4. Insulated tools or no? Specifically which tools should be insulated.
Pretty much all of my non-insulated tools are Klein except for a handful that are Ideal. I really like having individual screwdrivers although I have plenty of many-in-1 (among my favourite are Megapro & Wiha for different situations, and for more than just electrical)
My insulated screwdrivers are Wiha as they fit my hands best. I do have multiple sets of the Wera interchangeable driver/handle setup, but I rarely use them. Once or twice I found the insulation too thick but rarely. My insulated pliers are all Knipex or NWS. I don't have anything insulated besides drivers & pilers, not even nut drivers. For my uses, going into a panel or box it's just an extra precaution more than a necessity, but it involves trusting your pencil which even the best I have used are iffy from time to time.
As an apprentice you won't need a meter but it's a good idea to get the meters you see others using so you can both learn how it works and how and when your master is going to pull out which meter vs another tool. Personally I have Fluke 87V & 324+. I almost never use the clamp meter, but it did come in handy once to have an extra meter with the temp probe attached so I keep both handy. I have other meters on my bench (27/FM) and tool box (88V) but to bring to an outlet or panel I'd want the 87.
I'm not an electrician by trade but one of my jobs in college equated to electrical apprentice with some journeyman duties later on (changing outlets, breakers, switches, etc in dorms and apartments). One of the biggest tasks I did was stripping wire, either to prep for install or to assist with removal.
Anyway here are a few suggestions that I didn't notice anyone mention yet and are definitely not necessities as an apprentice but will augment any others that you purchase. Each one is pretty much 'every time I do electrical work' I am using one of these tools.
treat yourself to some really nice pliers. 10% discount with code thanks2gj
NWS 1096-49-VDE
NWS 1406-49-VDE
For stripping romex it depends on how old and ****** it is whether I use either one of these
Felo automatic wire stripper
Felo cable stripper
Lil' ripper stripper
some other tools that may make your day a bit easier
wet noodle fishing kit
tie lips
nut blaster