Yes, the LeClerc folds, but the folding process is for storage or moving the loom through doorways. Most of the time it will be open. The Hammett comes apart and is moved in pieces.
The Hammett has such a wide shed that you can usually weave unbalanced weaves. I think, but I'm not sure, it could be retrofitted with a shed regulator.
Yes, the shafts are supposed to lift off the pins. Unless, like yours, the pins are bent, or all ooked up with gunk. If you want to try gently bending the pin back I'd do it with pliers and a Jorgensen handscrew wooden clamp. Or use a couple of blocks of wood clamped on both sides of the wood frame, so you don't break the wood where it is drilled. I don't think I'd risk it.
You could just slide all the heddles to one side, polish the bar with 0000 steel wool, then rub with paraffin and buff (don't use beeswax or oily stuff and never WD40.) Then slide them all back in the other direction and continue.
OR, you can flex the bars out of their mounts, leaving the wood frame in the loom. Just remember to hold onto the heddles so they don't end up on the floor.
If your loom is set up with the solid beam and not the open beam extensions, you can fold the back beam up and fasten it to the castle without losing the tension when it is reopened. You may need to do some adjusting on the ratchet brake(s), but it should be fine... just don't get used to it that way! Too many looms get folded up "for awhile" and it lasts years!
Most non-weavers call all looms rug looms. You need to find out which model you have. Go to LeClerc's web site. They have drawings and diagrams of all their looms, both new and out of production.
Around here (central Virginia) counterbalanced 4 shaft looms go for about $400 for a 42 to 45 inch weaving width. Jack looms are somewhat higher, depending on condition, number of treadles and type of brake system and if they are still in production.