Lightbrite………
The size of a jury varies.
In CT criminal juries are 12 people plus 2-3 alternates. The longer the case is supposed to take to try then the more likely there will be 3 alternates.
Civil case juries are composed of 6 people plus 1-2 alternates.
Favoring someone with the same last name.
Here in CT, with the exception of Probate Judges, we do NOT elect judges they are appointed. The vetting process eliminates those who would have a predilection for bias.
As for arranging for better treatment in prison. Wardens don’t take orders from trial judges. The Corrections Department is part of the Executive Branch, not Judicial.