Getting married after khula

Q: I had khula in January 2021 due to circumstances and I have a baby as well. But I have strong feelings for my ex husband, even though I came to know he got married, but he did contact me and mentioned he missed me. After that he never mentioned it nor did we have any further conversations. I do feel I and him understand each other. Is it possible that by any type of prayer or dua I can get under nikaah with him again in any point of my life?

Having meals with non-mahrams

Q: Is it permissible for me to sit and eat with my girl cousins while her father, mother, brother and my mother are also seated there.

Also, can I say جَزَاكَ اللَّهُ خَيْرًا and speak about general things like Madrasah with her mother, who is my mother's brother's wife while they are wearing abaya and scarf but part of their hair or neck is exposed?