If you have a local Linn dealer that is going to install the parts or you are a detailed oriented meticulous person and want to do it yourself I would do the upgrades. Each of the upgrades you propose will significantly increase the sound quality. I have a LP12 which I have upgraded several times and have been ver impressed with the cost effectiveness of the improvements. In the end, you can take the table as far as you want to contemporary Klimax if you choose. A really great feature of the line.
If you are neither of the above then sell it and buy a new table. It is not that Linns are finicky or incredibly complex any more, they are precision instruments that must be set up precisely. A friend of mine is a Linn certified master technician and tells me lots of stories of folks that set up their own table and put on the wrong nuts, or did not level the internal springs and wonder why it didn’t sound right. Anyway, if you are not a detailed oriented person, like me, there are lots of great tables available.