After sifting through old newspapers and censuses, I don't think the Charles Cobb in your first image, charged with forgery, is the same Charles in the other images. This one was born around 1836, and can be tracked on the Wimborne Minster censuses, while the others can be tracked on the Bere Regis censuses, and their ages are half a generation out.
Source: Sherborne Mercury 24 July 1855
Dorset Summer Assizes
Trials of Prisoners
Charles Cobb, 19, pleaded guilty to forging certain
warrants and orders, for the payment of money, at
Wimborne Minster, on the 8th June. The judge
observed that he did not consider the case to be one
of the same serious nature as those in which promis-
sory notes and bills of Exchange were circulated, or
attempted to be circulated, through the country; but
still it was a grave offence, for the prisoner had de-
frauded a shopkeeper, and also his master, by giving
false orders to obtain goods and money and he had
placed forged names to the warrants for that purpose.
The offence of forgery must always be treated se-
verely, more particularly where it related to negocia-
ble instruments which passed from hand to hand.
The sentence was six months hard labour.
I also came across an article in 1863 that fits in the right locale of the other Cobbs, where a pair of first cousins (Levi and John) robbed a Samuel Cobb (who had at least two sons, named Charles and Daniel). Levi is from Wimborne Minster, so perhaps the forger Charles is a cousin to your Charles.
Sorry if this is all confusing, but there are a lot of Cobbs in Dorset, and a lot of them keep using the same name for their children for many generations.
