Domain name confusion

Intended name for my startup seems to be free to use. A search in global/eu/us trademark databases all returned no entity with the same name.

TLDs with my domain are either free or offered for sale in marketplaces, except for one that is apparently already owned with its website currently not accessible (error 403). Still, the TLDs that I've mainly wanted to have were not owned, and I had them registered.

I havent incorporated yet, and I heard that a registered trademark would be valid only in the respective country, whether or not this practice solves the question...what would you recommend to do here?

Apart from these, one business in a small town has my domain name coupled with complementary words (like, mine is "sky" and theirs "sky graphics labs"). They seem to be really operating around their own locality, in a country where my service is intended to start soon after launch. There is no immediate correlation between the two services, but this may not be the case later on, since the platform, once succeeded in other, more central, immediate areas, may well naturally extend to offerings of users who are active in the same sector as this business. Would this really become an issue then, in a single country? Considering that my domain name differs with one letter from a rather generic name, I expect some room for the likelihood of this small magnitude as far as coincidences like collision of domain names go :)

Not exactly sure what the question is, but I'll give it a go.

Desired domain name is available. Desired trademark name that matches domain name is available. Registered the domain.

Good.

I haven't incorporated yet.

Well - if you've gone through all this naming and global trademark search, it sounds like incorporating and then registering your trademark to that entity is the next step.

Trademarks don't extend to every country in the world.

True. IMHO, wouldn't worry so much about global domination and name confusion at this time. Basecamp used the domain Basecamphq.com until they got big / successful enough to purchase basecamp.com. Domain availability / name confusion didn't stop them from naming and creating their product basecamp.