EU Passport and playing overseas

First off, my apologies if this isn’t posted in the correct forum (mods please move if needed). I did search around and couldn’t find a detailed breakdown. I’ve done quite a bit of research and there are still a lot of gray areas that are unclear to me. I’d like to know what is exactly required to play overseas and try to go pro.

1. I do know that if you are under 18, you cannot play in Europe unless you fall into one of the 3 requirements. Parents moved for a reason unrelated to soccer. You moved between EU countries. You live within ~50 miles of the border of the country you want to play in.
Once a player reaches 18years old, are clubs allowed to sign you without a ton of red tape?

2. What countries do you have the best chance to go pro in that have established leagues? I know some countries have restrictions on foreign born players and limit roster numbers for outsiders etc. I’ve been told the best chance is in Denmark, Portugal and Sweden.

3. Does anyone have recommendations on a trusted company or organization for pro tryouts? There are a LOT online and it’s hard to see which ones are legit versus money grabs.

Reasons I ask... I coach a small local club with a few really talented players. I currently had 2 players move on last year. One went to Valencia, Spain. He has been training there over a year, but unable to play in games due to paperwork issues. He is currently 17, turning 18 in a few months.
The second boy just turned 18 last month, a local coach got him a tryout with a pro team in Latvia and he made the team. He has started a few scrimmages and scored a couple goals, but is being held back by rules that state only 30% of the players on the field can be foreigners. The other 70% must be Latvian. Are most other countries the same?

Thanks in advance for any insight you can provide.

 

Wow... great info. Thank you very much. I’ll look for the report online.