NPC friendships
Because NPCs need friends, too.

And this raises the even more troubling question of when is it appropriate to request a puppet in the first place? I imagine a big number of the requests are over stuff that can be done or learned from other players.

While friendships might be hard, the GMs have notes for each NPC and try hard to follow them. So if you make an impression there might be a note and the GMs do a great job following them.

but when it came to my puppet requests, NPCs have always considered our IC past/interactions and have always mixed it into my RP -- I obviously rarely have puppets where the NPC and I just chit chat (however even this has happened) but whenever I talk with an NPC that I haven't met before, there is always something in there, good or bad, that points to my relationship with said NPC

though this stems from the fact that a lot of my character's positions had me directly having an NPC boss and not a PC boss in the hierarchy -- which led to me having to receive puppets a lot more, thus leading to more NPC interactions with my PC and a lot more opportunity for relationships building up

Break out your fade to blacks admins. Let's do this thing. *rolls for success or failure*

PCs should generally be preferred over NPCs. There are exceptions but this is a good approach in general. Uuse the PC doc over the NPC one. The PC tender over the NPC one. The PC car thief over the NPC one. Players have one character to worry about and can afford to invest a lot more time and energy at one go. It's good for the player economy too.

You might have talked to an NPC ten times and feel that this means a lot but so have hundreds (or even thousands) of other people. You are just another face to them until you do something meaningful. Your perspective probably doesn't align with theirs.

NPCs are not there to solve PC problems. I'm personally not interested in a game where whoever schmoozes best with NPCs wins. They can provide an edge but, in general, I think it's better that we leave things in PC hands as much as possible.

One big aspect of Sindome's theme is that most people are business focused, out for them selves, have their own agenda and use each other. This applies to NPCs too. I actually find PCs that are all super friendly and open and who insta-bond with people far less themely than brief, business like interactions with NPCs.

It can be done. I have developed positive relationships with NPCs (even outside of gangs and factions) but it took a significant amount of time and work before I mattered to them at all. And even then they were still a bit on periphery. Which was fine for me.

I have been told that GMs specifically do not have NPCs engage in romantic or erotic RP as such RP should be optional and one GM doing it means all the others now have to deal with it. It stops being optional.

Some players (like me) actually work a little like NPCs. I prefer a series of shorter interactions that builds a relationship over time over a couple of monster sized chat session. Temperaments vary of course and that's fine.

Theyve seemed pretty real to me so far, and when they dont, Ive been able to fill in the gaps for myself (theyre busy with such and such, totally cant even hear you right now kind of thing).

Not everything needs to be solved with combat/theft, there are definitely ways of playing charismatic and outside-the-box thinkers and still get things done, although violence will always be a huge element of the game. Sometimes being a string-puller or sweet-talker is more about getting someone else to do the dirty work than avoiding it entirely, and when it comes to NPCs in general, always expect them to want something for their assistance or time.