Rami is a good tool if vendetta is in the pool I usually find. Late turn 1, reckless, double focus, 36" shot at his victim hopefully with rams from Lenny or a card held back to get the max damage.
You can either kill a wounded target or hurt it enough to get it next turn and finish it off. Pere used to be my go to guy for frame for murder, until everyone I ever played cottoned on and just went "Here take some conditions!". Now I rarely use him as his best effect is usually him dying. Although he can work nicely with Jug Rocket or the pigapult to add a speedbump in a bunched up crew. Young Lacroix I used to use all the time. Howeve now I use Old Cranky usually as i have enough firepower. When I first used YL I was obsessed with their "Gets into everything" until last night where I saw a new gremlin player having them focus shoot their normal guns with rams from lenny...... It was a volley of fire at just the right moment and with sever 6 damage (3 damage backlash reduced to 2 by lenny) isnt enough to kill themselves in one hit. Raphael Again I used to do exactly what you said in OP, dirty cheat + hard to kill (+slop hauler if you really want to) meant he was great for going off on his own (or with a slop hauler) and holding down a turf war marker. Dunno why I stopped using him really.... He's a lot of fun!
Edit: I forgot Merris! And I use her ALL the time! Merris I use all the time. Only 6ss? Reckless, Flight and the ability to drop a scheme marker 15" away? All good for me. She's kinda one of my scheme runners/suicide bomber. Plant Explosive is great fun when she dives 15" across the table and drops a scheme marker at peoples feet. I've even landed her in the middle of guys and had Ophellia try and shoot her to make her explode for all the burning goodness. Her fire bottle aint half bad either with 3 hits (it ignores cover) that's 9 burning on someone. 6ss of love for that little fat rocket powered gremlin.