I'm not sure specifically who Jon Franklin is without more context. He could be an ordinary person with a passion for sharing true stories, or perhaps a professional storyteller, journalist, or writer.
There could be a wise old wizard who gives Jon advice on how to hatch and take care of the dragon. Maybe there's also a rival of Jon's who is jealous of his discovery and tries to steal the dragon egg.
It's interesting because it can explore different aspects of their characters. For example, how their relationship might change if they were in different situations, like facing a common enemy or having to make difficult decisions together. It gives a new perspective on their individual personalities as well.
Jon Snow could potentially have allies like the Mormonts. They have always been loyal to the Starks. Maybe even some of the Dornish houses might side with him. They have their own reasons to oppose the current power structure in Westeros. And of course, his friends from the Night's Watch who left with him or believe in his cause could be his allies in this conquest. He might also gain the support of some of the maesters who see the value in his leadership for the future of Westeros.
He could develop a more overbearing sense of responsibility. Since he has these great powers, he may feel that it's entirely on him to save Westeros from all threats, whether it's the White Walkers or the power - hungry lords. This could lead to him making some tough decisions that not everyone will agree with.
The wildlings might be his allies. After all, Jon Snow has had interactions with them before. They are fierce fighters and could fight alongside him against a common enemy.
There's also 'Sister's Devotion'. In this fanfiction, the author explores the emotional connection between Jon and his sister. It shows how their relationship evolves from a simple family bond to something much more profound, especially in the face of the various threats that lurk in the Seven Kingdoms.
Jon might initially be resistant. He has his own plans and desires, and an arranged marriage goes against his sense of freedom. He could be angry at Catelyn for forcing this upon him.
Sansa Stark might be involved as well. Given her relationship with Jon Snow as his sister (though later revealed otherwise), she could play a role in protecting or being involved with the baby. Maybe she helps raise the baby in a world where Jon Snow is constantly facing threats.
Tyrion Lannister could be involved. He was close to Daenerys and had a relationship with Jon as well. He might be the one to help protect the baby or offer his wisdom in raising the child. Another character could be Ser Davos. He was loyal to Jon and would surely be interested in safeguarding the future of Jon's heir.