Abdul Hadi Pasha
Banned
As far as I can see Abdul Aziz was always going to succeed Abdul Mejid
There seems to have been an intermediate brother but nothing on him and if his mother was "unknown" I don't know if it would have placed him in the line of succession even if he was still alive in 1855
Abdul Aziz was 25 in 1855 so if his brother dies, he's going to take over the government
What might work, is the idea of Russian success at the start of the Crimean War, and an assault on the Ottoman defences before the capital. That might lead to rule by the Vizir or even the generals but not to the overthrow of the Sultan
Best Regards
Grey Wolf
There's no chance of a civil war based on succession by 1840. Even if you kill off Abdul Mecid, he already had sons by then. I suppose you could kill off Abdul Mecid and his sons somehow (maybe a plague?) but even then a successor would be found. A lot of people seem to think the Ottoman system was more Sultan-based than it was; when the empire was incredibly weak at the turn of the 19th c the dynasty dying out might have been crucial because many might have then considered the empire pointless, but by 1840 it had revived sufficiently that the establishment would have chosen a Sultan and that's that.