I'm [27F] returning to my old place of work; discovered that two Ex-Coworkers [28F, 40sF] tried to convince my boss against re-hiring me

I left a job I loved 2 years ago because I moved away. I've now returned to my hometown, and the previous company I work for advertised a vacancy. I applied. I was successful. All good so far.

However, I went in today to speak to my previous/new boss and he raised a slight concern that my past relationships with other members of staff might be a problem. Basically, during my last 9 months in the job I was going through a lot of personal issues (depression blah blah blah) which meant I stayed late at work as I felt safe there. This in turn meant some colleagues thought I was trying to show them up by staying later than them. At that point in my life I was very stressed out, and extremely hard on myself to succeed and go above and beyond. There were times where I discussed the lesser level of work of one co-worker with managers (something I am not proud of).

It turns out that a meeting was held where my name was brought up. Two members of staff (who I always felt I got on okay with professionally) are against me coming back and have said I will disrupt the dynamic of the team. I am good at my job, not so good with interpersonal relationships. Since leaving, I have had a fairly drastic personality change. I am no longer highly strung, I take a more relaxed viewpoint on things, and feel I am calmer and generally more chilled.

When I re-start, my plan is to basically start afresh and not hold any grudges (including against these two co-workers). I will go in, do my work well, help when asked, and socialise at a surface level. I DO NOT want to be dragged into any cliquey sessions where people are gossiped about. I worry however, that I'll be seen as stand offish and rude now.

Please advise me!

tl;dr: Ex-coworkers seem to have an issue with me returning to the company; how should I proceed? PS My social skills aren't great.