Let me take a stab at your questions...
1) You can specialize. Grinding in Wurm is a big effort, so specialization is paramount. I started as a chain armor smith. It treated me well, and I eventually branched out to other skills.
2) Your chosen specialization is completely your choice. Some skills are harder than others and require additional management activities (like fueling a forge or making sure your metal is hot). You can try to target a specialization skill that is marketable, but that can take months or years of grinding to produce marketable quality items.
3) Crafting out the gate is doable. In the early game, you focus on building up your house and deed, so crafting is a major part of that. Some later game items could require resources gathered during raid-like events (runes).
4) The game is fairly demanding, yes, but we are addicted to the game play, the skill gains, the people. You get out what you put in...
5) The economy is fairly active. Unfortunately, our populations are declining, so some marketable good don't sell as well as they did. Newer players often begin selling bulk items where quality doesn't matter as much. (bricks, mortar, planks, nails, etc.) Just today I saw someone in the trade channel looking to buy 5,000 mortar.
6) You should definitely try F2P until you hit a maximum F2P cap on a characteristic or skill. If the game suits you, a subscription is not too expensive.
7) You can settle anywhere that isn't already claimed land. You can get the feel of an area, deeds, people, etc. If you are a loner, you can settle somewhere far away from deeds or people. This can be hard because early survival is difficult. I died 12-times running away into the wild to settle my first deed. If you are worried about someone else's turf, ask in local chat.
If you want to talk some more or have more questions, feel free to PM me. I'm not the most experienced player (only 8 years or playing), but I enjoy helping new players.