Interesting thought - not sure. If you're using a standard 4'x 6' table with 'long edge' than it seems reasonable as the Grenadiers have a range that exceeds the table size (ei. 50" range vs 48" table). The question is do the Martians have a plotting system that allows grid fire similar to the humans. In this I favor a Yes on the question as they could fire pre-game barrage, but, don't forget to add the -2 to hit due to the lack of Scout targeting. I'd recommend that the Grenadier must be on the table for 'narrow edge' pre-game barrages, just like the humans artillery.
The green gas barrage could be a problem for entrenched troops as a pre-game situation. Would give the Martian player(s) a target to push Assaults, etc. towards if part of the line was already broken by the gas.
Pre-game gas attacks also seem pretty thematic to some of the Martian tactics in the War of the Worlds book AND historical events in the real world around the time of the AQMF setting. I seem to recall the martians using Black Dust on some cities, and of course in WWI gas attacks were a thing.
Do Martians have the concept of long range strategic artillery as opposed to tactical artillery?
I believe that the Grenadier can only fire Green Gas and explosives; no idea what the Martians have in the concepts, though one could argue that hitting the earth from mars counts along way towards understanding long range artillery on a strategic level. This begs the question that with the prey-that-stings getting better at killing their machines, could we see a "LIC" new Martian 3gen machine in the future?? They've shown the ability to construct tripods, how about a very large quad with many weapons and functions. Just using the AD tech, you count have multiple missile launchers, grenadier style artillery, and a few sunguns to really put terror to the battlefield. I won't be making one of these anytime soon mind you, but the "Ogre" as the few survivors called it is a fearsome beast... (yes, with a nod to Steve Jackson games).
I can see the Martians creating suicide drones that form a wave ahead of the main body and deliver a green gas or black dust attack, or possibly be animated Bangalore Torpedoes to clear obstacles. While I won't speculate on what Martians lack, concept wise, they show a strong focus on direct fire weapons.
The heavy artillery bombardment represents them shooting at the Martians as they approach the battlefield,not once they are up close and personal. To reflect the fact that they can't really tell at a distance which tripod is which,we randomize which tripod actually gets hit.
Hmmm I think that the earlier discussion on 'lobocattle' fits well with the idea of 'bomb drones'; large cattle lobo'd with a combination of explosives, gas, and dust would be a terrifying new weapon, especially to the Texas folks!