Lone Wolf Achievement Tips
Blood or Ivan (his special is super OP) would be my picks. Maybe Vicky, for me it is crucial though that character can reach dex 90 or more quickly, to have interrupt return fire twice – pretty crucial for solo runs, the whole dex tree is. Maybe Fox might be an interesting choice as well.
IMP lacks special skill and might be too weak – many mercs have bigger total skillpoint budget than IMP gets.
And I would not worry about leadership. With 1 merc only – there is no need to hold anything for long, really. And truth o be told – you wont be able to, as in normal game pretty quick you need a dedicated militia trainer. The only thing LED would be good for for lone wolf is travel speed, as it is affected by highest leadership person in the squad.
Maybe even more profitable not to hold anything as mines will spawn diamond shipments, 1 shipment is 1 week of Ivan.
You get quite a lot of cash from loot, too, digging artifacts in the mine near fleatown, poacher camp can also give 3k item for 1 bag of cash each X days of vendor respawn. On top of that – AIM STAR achievements during combat each drop 2000 into your account I think.