Hey there, welcome on board.
The Freikorp is a great place to start, the are a really well balanced crew and fun to boot.
I would never argue against the Convict Slinger, but I am not sure how much Ronin would add to the crew. Having played a good few games with the Freikorp, I would recommend picking up a heavy hitter such as Taelor, or even better The Viktorias !