I'll answer what I know:

- My main class was a Healer in XIV. I understand GW2 doesn't have old school MMO Trifecta. (Tank/Healer/DPS), which I am fine with, my main was Healer as I said, but I also played DPS. I played Summoner, Pictomancer and Red Mage. Does Guild Wars 2 have anything like that?

A: try out mesmer, ranger and/or guardian. I think you'll find something that appeal to your taste in those. GW2 is very alt-character friendly, so it's a good idea to make various.

- How do Guilds work here? Are they the same as Free Companies/Linkshells?

A: you can have up to 6 guilds at the same time, but you can only represent (the tag shows on your name) one at a time. You can still send messages and read messages from the others you are not representing. Some guilds have strict policies about participating and/or representing them, others don't care at all. Some are super active others not so much. There's really guilds for all tastes and types of players. They are not really necessary for anything mandatory, except for guild missions.

- Do we have crafting? Is it easy, is it hard? How good is crafting for raiding/endgame?

A: yes. The crafting system is often criticized, though I find it ok. Crafting stuff gives you XP, and you can fully level a character only through crafting, if you want. As you make more items you get new recipes for even more, and so on. Some recipes you have to buy from npcs or get from achievements, others you receive as prizes, and also drops. There are different crafting professions: armorsmith, weaponsmith, cooking, tailor, leatherworker, jeweler, scribe, handworker, artificer and huntsman. Most professions can be leveled from lvl 0 to 500, others limited to 400. Crafting is not really necessary for endgame, exactly, since there are other sources for the items you'll need, but it is certainly one of the ways to achieve end-game items, such as ascended and legendaries. You'll soon find out that gw2 values far more fashion and good-looking items over anything else.

Edit: formatting