Personally I don't think litter size has much of a bearing on the personality/habits of my b-kidz.
I have one basenji (Ozzy) that is from a litter of 9. To answer your questions…the only question that applies to him is is he more (or less) accepting of dogs not from his pack - that I would answer as more accepting. He is extremely easy going, friendly, pretty much chill. Wouldn't dream of resource guarding, not aggressive to people or other dogs, not fearful, pretty easy to train and not super independent...I've taken him to pet walks with 200+ dogs and he loved every person and every dog (I've have had a number of people say if they could guarantee they'd get a basenji with his temperament, they would have one in a minute). He left his litter mates at 12 weeks and came to my house at week 15 of his life. Extremely self confident.
I have another basenji from a litter of 8 (Brando). None of these questions apply to him...I'd say he is middle of the road regarding accepting of other dogs...neither more nor less. I think he left his litter mates (in Finland) at 9 weeks. Extremely self confident. Wonderful temperament - extremely playful and very much as wise-a$$ personality.
I have a 3rd basenji from a litter of 5 (Aaliyah)...she is EXTREMELY independent and hard to train. The world revolves around Aaliyah (at least in her mind) - EXTREMELY self confident - which I think comes from her being her dam's favorite pup in the litter. She is very food motivated, but if she doesn't want to do something, you could offer her filet mignon and she still won't do it - in fact, she won't even look at it. She was highly accepting of other dogs before she and Ruby had her blow out - now she pretty much hates all red & white basenjis and I would never trust her around one unsupervised - even male. She likes other dogs, just not r&w basenjis. She left her litter mates at 11 weeks. All this said, she has a great temperament.
My 4th basenji (Ruby) is from a litter of 4. She is the least confident of all my basenjis. Not super confident with people or dogs...just the make-up of her personality I think. She does not like to be approached by strangers - people or dogs - and must make the initial overtures in order for her to be comfortable. She will tolerate strangers who come up to her, but you can tell she isn't comfortable with it. Her litter mates left at 10 weeks - she was the breeder's pick from the litter. She has an extremely sweet temperament with those she trusts.
All 4 of my basenjis are extremely well socialized - been around lots of people and lots of dogs from early ages.
So why do you think all these things about large litters - aggressive, resource guarders, fearful, etc...?