Just started stripping my front beam today. Any advice on parts suppliers? Possible upgrades I should consider? Potential pitfalls?

avoid red urethane parts, check the shock tower lower  drain holes are clear and after clearing any dirt/debris out and put some preservative in whilst the beam is upside down.

Check out cunningstunt's threads, there's a lot of info there.

Ball joint or king and linkpin?

If it's ball joint it's pretty straight forward really. The only issues arise if you have to renew the inner bush. You can either renew the brass bush but will need to get a tool to fit that or get rid of it all and fit a nylon bush that replaces them complete in one bit. Best place i found for quality of parts and service was Custom and Commercial. You'll need a drift for both 45mm and 50mm bearings. I used a piece of 44.5mm alloy tube off of eBay for the upper and a 50mm scaffold tube for the lower one or if you have sockets to fit them. Put all the bearing in the freezer over night before fitting and grease them once in place and make sure you turn them as you grease them to get them full in the needles, you'll see what i mean when you do it. If you need any help PM me and i'll try and answer.

You started yet?