Mixing with other people depends on your own situation. They very often only award points for "needs prompting" if you have to have someone with you unless they are a specially trained person who actually helps you to communicate.
The reg 35 for ESA has no bearing on PIP as they are totally different benefits with different criteria. Reg 35 for ESA only refers to the effects of going out to work, not day to day living.
To be honest I think it all depends on who assesses you - my assessment this time was much more accurate and I have no complaints, despite at the time feeling the assessor was cold and disinterested. The previous time, the assessor came across at the time as concerned and sympathetic, but I ended up having to go to MR as the report was so poorly done and inaccurate.