Greetings Tsua'm Fio! Allow me to begin by saying you have done a wonderful job of outlining what you are trying to do with your units in your opening paragraphs. Your comments have certainly informed how I will analyze your list as I offer feedback!
Let us begin, shall we?
Unnecessary Upgrades: You have a good deal of "fat" in your list. Many of these upgrades are not serving any significant purpose in your list and appear to me to be mostly a points-sink. By trimming some of this down, you should be able to free up a good amount of points, and this will serve as an excellent way to add additional units to your army as your collection grows. Let's examine a few of these:
Bonding Knives: You have added Bonding Knives to pretty much every single team that can use them. However, the changes to 6th edition have rendered this piece of wargear almost entirely useless - in fact, some of the units you have it on can never even activate them. In the very rare case that your bonding knife becomes active, and the unit has not been completely destroyed, you will have a mere one or two models still alive, which is far below an effective fighting force. By removing these, you will have freed up enough points to purchase more models than you will likely save by using the Bonding Knives in the first place.
Blacksun Filters on Fire Warriors: These are largely a waste of points. On your smaller Fire Warrior squad, the BSF does not effect their Markerlights at all, and I don't imagine they will be using their other weapons very often at all, and certainly not on the turns where Night Fighting is in effect. On your twelve-man squad, I am led to understand that they come in from reserves, which means they are not even going to be on the board for 50% of all night fighting scenarios. In addition, it is a rare case where the cover granted from Night Fighting will be relevant against S5AP5 fire, especially when fighting against marines. Your battlesuits (crisis and broadside) and Hammerheads should certainly keep their Blacksun Filters (provided they are always starting the game on the tabletop and not in reserve).
Sensor Spines: How frequently do you find your vehicles taking dangerous terrain tests? There are rather few effects in the game which can cause a skimmer to take a dangerous terrain test, and many of them can be avoided by good movement and positioning. Unless you are playing against a lot of the weapons which can force DT tests, or playing on ultra-terrain-dense battlefields, you should be able to get away without these.
Grenades: You have spent a good deal of points on defensive and EMP grenades. Odds are, if a squad of Fire Warriors is unfortunate enough to be charged by an opponent, they aren't going to make it out of that combat alive, with defensive grenades or no, and especially not if the squad wasn't at full strength to begin with. Your Fire Warriors also should not be getting within assault range of enemy vehicles, especially if they have to disembark and wait a full turn before they can charge (after coming out of reserves, no less). If you are at a point where you need those Fire Warriors to blow something up, you are probably losing that game already.
As written, your Shas'O only has two hardpoints filled in, and is not technically a legal selection. Did you intend to have a Twin-Linked weapon on him? Or perhaps the Multi-tracker was not intended to be hard-wired? I can also understand the selection of Target Locks on the bodyguards, as they do help you to minimize overkill by spreading your shots around. However, Missile Pods are not exactly known for their overkill (it often takes shots from multiple Missile Pods to drop even a Rhino). This is especially true in 6th edition, where it is ever so slightly harder to "one shot kill" vehicles with out AP1 weapons and so you often rely on Hull Point kills to finish off vehicles. For this reason, you might be better suited to having Targeting Arrays instead of Target Locks on your body guards for the improved accuracy. This is entirely a personal choice.
Lastly, your 6-man Fire Warrior squad seems to be trying really hard to be Pathfinders. Why not just make them so? You will get more markerlights to use and, by moving the dedicated transport from the 12-man squad to these Pathfinders, can utilize the Marker Beacon to assist your Deep Striking units. I understand that this means your 12-man squad cannot use the tank when in reserves, so it will require a minor change to your general strategy (by starting the tank on the board) so this is largely a personal choice. However, I do believe that it will help the synergy of your list overall if you do this.
Victory needs no explanation, defeat allows none.