Peter's a tricky little rat, isn't he? I don't like the guy, but I'll do my best to answer your questions.
I don't think he does.How do you think he feels about his betrayal? He is obviously still faithful to Voldemort, so he can't be too remorseful, but do you think he feels badly at all?
If there was a time to feel bad, it would be when he joined the DEs, when James and Lily died because of him, when Sirius was sent to Azkaban. If those things didn't cause him to turn away from the Dark Lord then I can't imagine him feeling any kind of remorse.
We need to remember that unlike most people, he didn't have to return to the Dark Lord when he did. Peter sought him out. He helped bring him back to life. Peter made a conscious choice to bring back the evil. Voldemort was weak, he couldn't have hurt Peter. Peter could have left him that way, but he helped.
I would assume he struggled with the idea at first. But he made his choice and don't think he's given it much thought since.Before giving the information to Voldemort, do you think he went through any internal struggle with himself or didn't even care?
This has always bothered me. Why was Peter turned into Snape's slave? Peter helped to bring the Dark Lord back. He must have been held in good favor for it. I always had the feeling that sometime during book five Peter did something to upset the Dark Lord.When he's waiting on Severus Snape, stuck in his home getting wine like a servant, do you think he ever wishes he didn't do what he did and chose a different path?
Anyway, that's not what you asked. During this time I think Peter was bitter. I don't think he regretted anything he did. I think he regretted that nothing he did put him in high standing with the Dark Lord. He's upset because he has been turned into a slave. He is not upset because of the horrible things he did.
I think he probably did once. Something must have caused him to turn to the Dark side. Whatever that was, also caused him to lose the person he used to be.He likes to be on the winning side, with powerful people to protect him, but do you think he has any morals of his own?
Same as the last question. I believe he once thought of the Marauders as his brothers, but the feeling was lost. I don't believe he just woke up a different person one day. There must be a major piece of information about Peter that we're missing. But I do believe there was a time that he loved his friends greatly.He obviously doesn't have the same sense of friendship, loyalty and bravery that James, Sirius and Remus all had, but do you think he did care about the other Marauders, appreciate their friendship and love them like brothers at one point?
I hope my rambling was helpful. Peter really is hard to figure out. His motivations just don't make sense.