Presumably, although now effectively a dead rubber, if any City player receives a RC in the 2nd leg they would be suspended for the final.
I'm not certain on this one.
The situation with yellow cards was changed so that a player would be suspended from the same domestic competition for an accumulation of yellow cards - so 4 yellow cards in the league and one yellow card in the league cup before Christmas would no longer result in a suspension.
I'm not sure this is the same for red cards though - certainly I seem to remember Vardy being suspended for a League Cup game after being sent off in the Premier League so I presume a red card would result in a suspension from the forthcoming league/FA Cup games rather than the League Cup final - otherwise the Grimsby player who got sent off against Palace in the FA Cup last weekend could theoretically have their 3 match suspension carried out over 3 seasons if Grimsby only played one FA Cup match in each!