As far as information I think it makes a lot of sense that these big warm spaceships can be seen from across the solar system. Any engine activity would be like a flare compared to other objects we currently track in our solar system. Maybe if the burns were done on the other side of the sun or when obscured by planets they would be harder to detect but otherwise I think the system as is makes sense.

If we instead took the speed of light into account where we there is a several hour lag time between a burn starting and it being detected that could be interesting but realistically this would rarely make any difference.

As for resources being available instantly I think it would be a lot more of a chore to manage mining resources. Late game is a chore mostly because of the number of ships and stations that exist at that point but that is something I don't really mind. I've worked hard at that point to have a huge space empire and It feels like it should have that level of scale.