Rajnish
There are a bunch of questions here:
1. Pushkal was the younger son of Mandavi, so even if one assumes that Kush, Luv, and the older sons of LBS Chandraketu, Taksha and Subahu were born, they'd just have been 12. Nothing is said or known about the other 3 sisters having twins, so Pushkal must have been 10 or 9? The only way Pushkal can be the age shown is if Bharat and Shatrughan had their kids during Rama's vanvas. In that case, assuming Taksha was born say year 2 of vanvas and Pushkal year 4, Pushkal would have been ~22 at the time of this yagna, in which case he could have been married, and a commander. Still begs the question - how was Pushkal chosen for this assignment?
2. In all the accounts of Janak I've read, he and his brother are son-less, and unlike Dasharath, he never strove for any sons. Then how does he have a son here, and why would he continue to act like a vassal of Rama despite Sita's exile? Sure, Rama did rajdharm for Ayodhya, but Mithila isn't obligated to continue to be a vassal of Ayodhya since the basis of this alliance - Sita being maharani - is no longer valid.
3. In both the Valmiki and other accounts of the yagna, Rama's army (irrespective of who led it) went unchallenged throughout the yagna. In Valmiki, even Luv & Kush didn't accost it. In the other accounts, they did. But in this account of yours, just about everybody wants to stop/steal this horse.😕
4. Pushkal actually gets killed during this expedition?😕 (Even if he's revived later?) Also, what were the other brothers - Taksha, Chandraketu, Subahu, Angad et al doing?
Anyway, thanks for posting this fascinating story.