Current space ships have extremely little ability to adjust their trajectory on more than a very occasional basis.
Yes. And assuming you have a laser or relativistic weapon, even with an amazing ability to dodge, the first to detect will fire and "simultaneously" (from the target's perspective) obliterate the target before the target notices they are even under attack. I'm assuming near-term space combat would be decided by stealth, not firepower: anybody detected is destroyed. Probably the only way to return fire would be to have drone fleets surrounded by dust, so that somebody survives to see the laser passing through the cloud and get some sense as to the direction it came from.
Also, it's possible that any significant combat in orbit would destroy everybody involved: see Kessler Syndrome/ablation cascade.