Young LaCroix aren't as terrible as I may have led you to believe. I think they have a place in an Ophelia led crew when paired with some one key model, the Slop Hauler. That is not to say that the Young cannot be effective without one, I just find that bringing one or two along not only helps with Dumb Luck, it also helps when they can drop a models defense value to four, the same as a Young shooting. The Young have a decent defense of five paired with a pitiful willpower of three. When you couple this with the whopping three wounds Young are not long for the world. They have a very good walk of six allowing them to keep up with Ophelia. They have Insignificant, so they cannot take interact actions and they are also Peons so they won't count for most strategies. One thing that can help keep them alive is the Small Target ability that gives an attacker that is using the Sh stat a negative flip to hit them. The Young also Get Into Everything, allowing them to take Attack Actions on Ophelia's upgrades at a -2 to the Sh stat. So they can fire Ophelia's upgraded guns but they will discard the upgrade after they use the attack. It also suffers from -2 Sh so they are always firing at Sh 4.
The Young have one Attack Action and one Tactical Action. The default attack for the Young LaCroix is their Much Abused Pistol. This has a range of 10-inches and a damage profile of 1/3/4, on a Ram they can trigger Dumb Luck and up that damage to 2/6/8. Now the moderate and severe damage will kill this model in most cases since they take half of the damage the target suffers. The Tactical Action allows them to attach one upgrade with the restriction of Ophelia to a friendly Ophelia as long as she doe not have the upgrade attached already.
The Young LaCroix can be effective models when used correctly in an Ophelia led crew. They not only help Ophelia stock up on guns but can also run around and use those same guns as long as they are within 6-inches of Ophelia. I find that often the best use is to try and focus with them as much as possible. This not only gives you better odds to hit, but it also gives you a likely cheatable damage flip against whatever target you hit. This can make for some powerful combinations that allow the Young to go out in a blaze of glory while possible taking out a model that can be up to four times its cost. Since you can have three of them you can always use Ophelia's (0) actions to place them around her so they can use focus and shoot. Using Ophelia's upgraded guns these little monsters can get downright scary. If you can focus using an upgrade the Young become extremely dangerous, luckily for your opponent they die rather easily if you can get close enough to engage them in melee. The upgrades do give them access to some interesting options though.
This gun gives the Young access to a 12-inch gun that ignores line of sight. Since they can be within 6-inches of Ophelia to use it they have an effective range of 18-inches from wherever Ophelia may be positioned. Half of the board ignoring line of sight with a 3/4/5 damage profile turns them into little mortar men.
This gun gives the Young access to a blast based attack that will only do a maximum of one damage. The key is to maximize the blasts with moderate and severe damage since everyone damaged by the attack will gain Burning +2. this attack does ignore cover so a focus here gives positives to attack and damage allowing you to do a maximum of 1 damage and burning 2 with three blasts on a severe. This has a range of 10-inches allowing an effective threat range of 16-inches from where Ophelia is standing.
My Threatnin Gun
This attack was so ridiculous that it is the only attack action to get errata'd. This attack deals 3/5/6 damage at 10-inches. It also makes the target pass a TN 13 Horror duel after being shot by it. On a Ram you get the trigger of not only the original target, but everyone within a pulse of 3-inches must take a TN 13 Horror duel. The effective range is about 16-inches from where ever Ophelia may be at that point. This attack is supremely effective against crews that like to bunch up together.
Keep in mind that one Young can reload Ophelia and then attack during the same turn. You won't get the benefit of focus but when run with Slop Haulers lowering defense this allows for multiple shots from the same upgrade per turn. So if the target you want to hit you can't see, use the Jug Rocket. Between Ophelia and her Young LaCroix this allows the upgraded guns to be used around 4 times per turn. Using the Threatnin Gun and hitting can make for some interesting models that have to pass a Horror duel, using it four times and paralyzing the enemy, priceless. (note this hasn't happened though I'm sure someone, somewhere will have it happen then complain about how overpowered either the Threatnin Gun, or Ophelia herself is.)
Hope this helps and presents the other side of the Young LaCroix argument. Hopefully have an in depth look at Ophelia herself at some point.