I have huge collection of ships (all three factions) from 1st edition. Naturally, despite the fact that I never wanted a 2nd edition (1st was perfectly fine, patches would fix anything problematic) I will dive into 2nd edition, given the fact that it is the most popular miniatures game in my area. Now question is - what do I have to buy to have good collection of cards/upgrades available?
From what I understand Conversion Kits and Base Game will give me all needed cards - is there something more to it? Should I be prepared for buying 6th X-Wing or 4th Fang just to get card unavailable otherwise?

P.S. I would like to focus on Rebels at the start.

The 3 conversions have any wave 1 content for their respective faction. Past that you get a good starter mix of pilots and upgrades and crap for tokens, ie the focus/calculate/etc. The new starter is pretty much mandatory and the list of ships converted, BY DIAL, are listed in the xwing 2.0 faq found on ffg’s site. So conversions are a great starting point but in no way complete, expect to buy more stuff. There are videos with complete contents do a search for unboxing videos. You can stay single faction if you wish and it only requires patience but if you like op competition you will be rewarded playing multiple factions as power curves ebb and flow.

Tl/dr, get a starter and rebel conversion if you want to be conservative. Want to convert everything, expect multiple conversions and no real sense as you are better off getting the shipless conversions later for any wave past 1.

https://www.youtube.com/watch?v=bsY59idxRBU

https://www.youtube.com/watch?v=bWmzvvx3rjA

https://www.youtube.com/watch?v=M_cJyUKTRto

Stuff. Click on "FAQ".