The OP asked for views, so here's mine.
Buy a new Majik-level LP12 if that's within your budget. For your hard-earned, you get a plinth variety of your choice and the best bearing Linn has ever made. You'll also have the privilege of a brand-new LP12 with no question about its provenance or state of wear. Over time, you can upgrade the PSU, tonearm, sub-chassis as and when opportunities arise. In the meantime, you'll have a deck that's visually to your liking, with a sound that Linn intended.
Going down the second-hand parts route and cobbling together an LP12 of mixed pedigree is just too fraught in uncertainties for me. But starting with a known baseline, you can better judge whether the next incremental upgrade takes you in the direction you want. That being said, do have a listen to a Majik LP12 first and see if that alone floats your boat.
FWIW - the view from Cymbiosis is that using a new base model, they will build a better sounding Linn than the Majik for the same price or cheaper.