in the house of a pharisee (i.e. a member of a faction that is anti-Jesus),
Peter is the guy who attacks Jesus
This is, mutatis mutandis, the reflection of the case when
Jesus attends sinners and publicans
the pharisees attack him
That simmetry is broken in Mark, where we have the latter antithesis (Jesus with publicans, attack by pharisees) but not more the former (Jesus with a pharisee, attack by Peter).
In addition, the fact that Peter is meant as bothapostle and sinner is reflected partly in Barnabas:
And when He chose His own apostles who were to proclaim His Gospel, who that He might show that He came not to call the righteous but sinners were sinners above every sin, then He manifested Himself to be the Son of God.
Reading Mark, there is nowhere the idea that Peter was a sinner. Barnabas is clear in pointing out that Peter was a sinner before that he would have denied three times Jesus (I am conceding here that Barnabas knew that Peter was the name of an apostle and that Barnabas knew at least Mark, which is far from being true).
The only time in Mark where Peter is a sinner is when Jesus calls him "Satan". But that is a typical marcionite point: Peter is Satan since he hails Jesus as the Christ, which is simply not true for Marcion, while it is true for the rest of Mark.
Note the anomaly in Mark: Simon the Leper would be the only person named in all the Gospel who is not a disciple of Jesus (technically: an outsider) and who is an enemy of Jesus...
....contra factum that in too much commentaries on Mark (and even by Kunigunde herself) I have read that a feature of Mark is that named people (basically: the apostles, i.e. presumed insiders) are described poorly while the anonymous outsiders are described positively.
Evidently, to go against his preferred style, Mark had to give some concession to his own embarrassment about the identity of that Simon.
My point is that in *EV the named people are all described poorly, none being excluded. Well, apart Pilate.