I have developed some concerns with this portion of the map (see screenshot in spoiler and title of post for location) after spending hours on end trying every tactic I know to capture it (to the point that I went from ~900 rp to 0 from dying so much). Note that I am not trying to capture it on my own and that the commander has it placed on the map as the next place to capture.

The concern here is not simply the difficulty I'm having with capturing it, but the way in which my AI allies approach the target (spawning from Village, Residence, and Aqualand ---> Here's the map) making it so difficult and requiring hours of effort.

The problem I'm seeing is that the majority of my forces are trying to attack this area (beginning the assault at the graveyard) by climbing the ladder to the left of it. This creates a GIANT choke that is forcibly dripping my soldiers in whereas the enemy gets an easy surround due to the easily accessible open spaces. Not only is the AI attraction to the ladder a natural choke point, but the AI is hardly efficient at managing ladders in the first place..making the efforts in capture all the more difficult because many will stay down off the ladder for way too long before trying to climb it.

To give an example, I decided I would take cover at the "allied" end of the cemetery (where I'm standing in the screen shot) with an LMG to give covering fire while my AI dudes rushed in. I spent a solid 2-3 minutes just mowing the enemy down, single-handedly preventing them from advancing and even completely removing their presence from the graveyard for about 20 seconds at one point. The problem is that only three or four AI soldiers managed to make it up there...each dying shortly after. I look to the left at the bottom of the cliff and there were over 10 dudes just chilling at the bottom of the ladder.

Even though I was excelling at my job for my team, my team failed to follow up because of map design (or AI competency depending on how you look at it). Almost NOBODY (even though it's just as close) was approaching through the village entrance, they were almost always trying to come up through the ladder. Because of this, opportune times for attack failed miserably because I was only receiving a small trickle of reinforcements (yes, I did also spend hundreds of rp on paratroopers, each of which failed because of 1) lack of reinforcements from main army and 2) tactically advantageous enemy position using open spaces for easy surrounds) due to either AI programming or the design of this map. I even did a solo stealth mission to cut off their reinforcements from and capture the Diving School to get the area in a deeper surround..still to no avail even with a successful capture and defense of the Diving School.

I believe that a large source of the difficulty in capturing this area is due to the map design not allowing the meat of the army to fluidly access a position from which they can successfully launch an attack.

My proposed solutions, broad and open ended as they are, are to either 1) alter the lower left hand portions of this graveyard area in a way that allows the AI to more easily access a position in which they can at least fight in the graveyard, or 2) do something about the way the AI handles ladders/chooses appropriate pathing to target zones.

attacking the Memorium from the north-west instead of the south-east should make it easier. For myself I barely attack the memorium directly from the graveyard as it can be painful, especially it the enemy has a tower there (did they?).
In your case I suppose that the commander AI launched the attack from copabanana to memorium, rather than village -> memorium?
Also using the hedgerows as cover isn't very good as bullets go through but I guess you know that already. Placing a sandbag might have been a better choice.