If a squad is being assaulted, and the defending squad is in a clear hex in an entrenchment and a another defending unit (which will add support the defense of the assault of the entrenched squad) is in the same hex but not in the entrenchment, how is the defense dice roll applied when the attacker rolls his attack / defense roll; 1) +2 for both entrenched and non entrenched squad, or 2) +0 for both entrenched and non entrenched squad, or 3) two separate defensive dice rolls for the defensive dice roll portion of the attacker's roll, or 4).....?

Hullo,

If you have two squads in a clear hex and one squad is in an entrenchment, you will roll two cover dice. If each squad is in an entrenchment you will roll 4 dice. COVER BONUSES FROM FORTIFICATIONS ARE CUMULATIVE.

To expand on that question, would any officers, elite infantry or medic squads increase the number of defence dice during an assult?

There was a discussion about this before; Elite and Officers provide cover in supressive attack. An assault is considered a normal. Therefore, extra dice for elites or officers isn't provided.

Though a medic squad in the hex will give you one more defense die.

von Stichen said:

Yes, but only in case you are a defender.

If you assault with whatever squad, you get no bonus to defence, unless your attacking squad has a special "medal" token (see Normandy medal tokens).