Unless the unit token has a specifically marked Firing Arc (see Firing Arc, BRO, P.14) then any weapon is basically 360 degree.

Before I answer your question about combining special abilities, I want to check one thing: If you are using a Heavy Vehicle, then there are 2 sets of abilities, those for the Primary Weapon (red border around the abilities) and those for the Secondary Weapon (those with a yellow border around the ability). You cannot use Machine Gunner on a tanks main gun, just to be clear.

Fire on the Move allows the unit to take a Firing Action at some point during a Movement action, so the unit can choose some point at which to fire, then resolve a Firing action, then finish resolving the Movement action.

Machine Gunner allows a unit which is taking a Firing Action to shoot at several enemies, so when shooting the unit can split up their bonus.

Suppressive Fire allows a unit taking a Firing Action to double its combat value, so this is also legitimate during a Firing action, even when on the move with a machine gun.

If you want to know the details on how these all work together, check the Reference Charts on P.32 (specifically, the Reminders on P.33).

There is a Move Sequence wiht the details for a Movement Action (including when you can Fire on the Move) and the Firing Resolution reminder that covers exactly when various modifiers are added in, when doubling occurs, and when you can split the Combat Value amongst different targets.

We were playing scenario two and one of the spaces on the board had a defense bonus of +2 for infintry identified on it's left edge but then on its other edge the same space had a defense bonus of +1 for infantry. What does this space grant for infantry defense bonus?

It is Terrain piece C6-A from the Heroes of Black Reach. It is printed on the board (the cluster of four squares giving a defense bonus to infantry in the bottom left). I am new to this game. But I think two of the edges (left and right) have symbols indicating that the cluster blocks line of site, light and heavy vehicles can't enter, Infantry must stop once the unit enters and infantry receives a +2 defense bonus if they occupy the cluster. While the other (bottom) edge of the cluster seems to have a symbol indicating that infantry that occupy the cluster receive a +1 to defense.

I've now played my 3rd game, and am really enjoying it.

However, though I think I'm doing this right, I wanted to check…

A Ranger Fire Team and SS Panzergrenadier Fire Group are fighting between a Hedgerow and small building.

Because we don't count the square for the firing unit or the target, LOS is clear. If there were a Terrain Element between the two with a -2 red triangle, then it would be subtracted from the attacker's roll (which is Combat Value plus the die roll).

However, the defender's Defense Value is increased by the Defensive Bonus of the Terrain Element in their square (+2 for the Hedgerows, and +3 for most small buildings).

Am I doing this right?

Thank-you for the confirmation!