Yes, to suit 42/44 only and yes, boss is threaded.
As above with e-type BB's, where required I use a standard 107 BB to achieve correct chain line, take care with BB mounting and say a little prayer 🙏 (no problems so far....)
Out of curiosity I had a look anyway and all are adjustable in two positions from LX to XTR via a little 'flip chip' and two position mounting bolt slot arrangement.
Left to right: LX 569, LX MEGA 9, XT M739, XT M739, XTR M950.
Apologies, I misunderstood your initial post - I thought it wasn't moving at all 🤦
Some e-type front mechs adjust with alternate mounting holes on the bracket interface but I don't think the LX had that facility.
I can grab some photos of the alternative e-type's if interested or as above you...
Does it move out you pull (sideways) on the cable directly above it?
Is it bent? Have you tried drenching it in penetrating oil?
The derailleur unsurprisingly isn't unique, it's an 'e type' and can usually be found cheaply on eBay.
The RHS crank will have to be removed for any replacement.
If...
Wish it had been an easier path through for you but glad to hear it's done and you're home safe.
T-shirt made me laugh out loud and for a moment I thought you'd got a mohawk!
Best wishes for a full and smooth recovery 👍
Certainly not perfect (mainly owing to gloss Vs matt finish) but some P2's are very close to raw ti...
Not suggesting for a second on your build but a happy accident on mine that I'm pleased with (excuse the pig ugly headset!).