Artillery Reposition

How can this card used together with a "Bombard" command card, because both cards are either contradictory or to powerfull (if you are allowed to move 6 hexes e.g.)?

The two cards really do not work together, therefore the combination of both cards are not allowed.
(Richard Borg: 2015 - June - 28)

The Fire and Hold command card is similar as the Bombard command card. So the Artillery Repositon tactician card can´t used together with "Fire and Hold" also?

Right. Because the Fire and Hold Command card states, “Units may not move before or after combat…” would not allow the Artillery to reposition.
(Richard Borg: 2015 - July - 07)

If i play La Grande Manoeuvre, can i move then additional 3 hex with Artillery Repostion?

No! The usage of Artillery Repostion along with LGM would make no sense, because Artillery Repostion would reduce the movement from 4 to 3 hex.
(Richard Borg: 2015 - July - 11)

Is a battle of the ART compulsory required to use 2nd option "or move 2 hexes after it battles" or is the battle not mandatory as all battles.?
E.g. A cavalry and artillery does a combined attack, but CAV is forced to retreat/bounced, so the ART lost his battle option. Can the ART use the TC and move 2 hex yet? Another example if the Cavalry battles first independent and is bounced again and blocks now the Line of Sight of the ART, so the ART has no target?

The artillery unit does not have to battle in order to move 2 hexes. If it was ordered to battle and some action caused it not to be able to battle, it is still considered to have battled in reference to the Tactician card
(Richard Borg: 2017 - 11 - 29)