1) Then you could just fly past outside of normal spacetime.  FTL jammers are worthless, as is the mine field. I certainly can't attack something in a dimension I can't access.  And warp drive doesn't remove you from real space, except in Star Trek, it just moves space around you.  Hyperdrive would, but I can't access hyperspace.  The field would have to be laid out as a continuous field, and prevent passing or slow down ships that pass through it to be of any use.
For example, Interdictors in Star Wars produce a gravity well that prevents hyperdrives from activating.  They are used to block ships from jumping away from battle and to make them revert to normal space when they enter an area.  If they couldn't pull ships out of hyperspace they couldn't be used to block starship travel through certain areas.

2) So I can somehow guess the exact point where you are going to leave hyperspace.  I thought I only got a vector at best, as you could leave whereever you wanted, and my weapons can't enter another dimension.

3) "After 20 years of peace under the ceasefire agreement in SA2018 a new war is about to break out. Wishing to finish what they had once began the Dominion launches a surprise attack through the neutral zone. Using meticulous use of intelligence and planning they launch a rapid strike against the FPA borders. But first they had to blast their way through the mine field...

Basically this is an open space battle with a certain spin. The Dominion must assault a fortified FPA territory. First line of efense is FTL jammers and a mine field. Dominion has intelligence report on the location of most mines thus they can clear it away efficiently though they still need to be careful otherwise they alarm the FPA forces too soon. Next stage is the various space bases and other fortification in the area, reinforced by the FPA players' fleet. FPA has the advantage in direct combat but their position is known and the enemy has the initiative. Thus the scales balance out."

This doesn't mention whether it's in a star system or interstellar space.  Now that I know that, though, I can alter my plan for use in interstellar space.