Okay, time for another big-as-balls post.
Just on a whim I decided to use my 3025 TRO and Sarna to go through all the Macross-derived mechs and see which variants would be possible to use... Time-line appropriateness being a little flexible in this case as we don't know when or if PGI would get around to adding them... So the MWO timeline could be upwards of 3057-3067 depending on how long it all takes.
So, without further ado, here we go.
Stinger
3R, 3G/3Gb, 5M and the 6L all seem most appropriate. The 5R and 6S are maybes, since they mount stuff like Rocket Launchers, LFE, Small Cockpit and Light Weapons. Don't know how the RLs would be implemented. Not sure what the difference is with the "Light Machine Guns" on the 6S there, as on Sarna the LMG is listed as 0.5 tons IS and 0.25 tons Clan, which is already how MGs are in MWO.
Wasp
1A/D/K/L/S/W... Wow got a bunch of variants right from the get go... But continuing on... 3L/M/S/W. Not much variation in names, but certainly a myriad of weapons loadouts. Even a couple variants specifically used by Wolf's Dragoons. Only the 3L is iffy, again because of the RL weapons.
Valkyrie
QA/F/D/D1... Just enough variants to meet the minimum 4 variant initial set. Only thing the IS needs for the QD1 are Targeting Computers and those have to be relatively easy to add in since the Clans already have them.
Going by the 3025 TRO, the Ostscout would come next, however I don't see this mech being put into the game, as the mech was designed to be as pure a scout mech as it could be. The mech would require obscene levels of hardpoint inflation, to the point of it being a "scout" mech is pointless.
Phoenix Hawk
1/b/c/D/K/Kk, 2, 3D/K/M/PL/S, 4L/W, 6D, 7CS/K/S... Wow, a vertiable cornucopia of variants for the good old PXH. It even has a couple canon Hero mechs to go with it. The onl 2 ifs I could find here were the 4W with its "Heavy Duty Gyro", Light PPC and "Improved" JJs, and then the 8CS with an XXL engine and XL gyro... The big problem is none of the variants on Sarna gave dates as to when they were introduced.
Ostroc
2C/Cb/D/L/M, 3C, 4C/L. Some good options here, the 4C being the only outlier due to mounting Rocket Launchers.
Ostsol
4D/F, 5D/M, 6D, 7M, 8M. Again some good options to use. The 5D mounts Rocket Launchers, but the 6D is the big outlier here. Triple Strength Myomer... How in the hell would PGI implement that? So far the 6D is only the second mech I've seen that mentions a Targeting Computer.
Rifleman
2N, 3C/N, 4D, 5D/M, 6D/X, 7M, 8D, 9T... A pretty good spread. The 8D is the big outlier here, mounting those Rotary AC/5s.
Crusader
2R, 3D/K/R/L, 4BR/D/K, 5K/M/S, 6M, 7L/W. Once more quite a decent selection of mechs. This time the 6M and 7W are the outliers. The 6M with its Light PPC and MMLs, and the 7W with its MMLs, XL Gyro and Light FF... Also, wow, those MMLs might not be such a good thing after all... Capable of firing either LRMs or SRMs... Got another instance of the Clan AC/LBX ammo switching dilemma there.
Archer
2K/R/Rb/S/W, 4M, 5R/S/W, 6S/W, 7L, 8M, 9M/W... I think that's pretty much ever Archer variant save two, the 9K and 9KC, due to those two mounting MMLs, but also "C3 Slave" and "C3 Boosted Slave", since MWO already treats every mech as having a C3 system of some kind.
Warhammer
4L, 6D/K/R/Rb/Rk/L, 7A/K/M/S, 8D/M, 9D/S, 10T... The good ol' Warhammer. There were quite a few variants left off this list, mostly due to them being timeline inappropriate, appearing either during the Jihad or the Dark Age, or using "Experimental Technology". Surprisingly only one variant uses MMLs, but, becaue of their ammo switching ability, I left that off the list as well.
Marauder
1R, 2R, 3D/L/M/R, 4X, 5D/L/M/R/S/T, 7D, 9M/M2/S/W/W2... Wow, that's a lot of possibilities for the Marauder. The first big outlier we have is the 4X with its Binary Lasers, then we have the 5L with its Triple Strength Myomer, the 5R, 5T and 7D with RAC and TC, the 9M2 with its Heavy PPCs, and finally the 9W/W2 with all sorts of things... Snub-Nose PPCs, Improved C3 and JJs, and finally Heavy Duty Gyros. Still, all things considered, there's plenty of Marauder good-ness to go around.
And finally we arrive at...
Longbow
0W, 7V, 12C/R, 13NAIS... Just enough to meet the 4 variant requirements. There are a few more, but they all mount those pesky MMLs. The 0W suffers from CPLT-A1 syndrone, mounting only LRMs and nothing more. The 7V, 12C and R seem like the best ones of the bunch, but I have to admit I would love to see what the 13NAIS looks like.
Now, I left off the "LAM" versions of mechs such as the Wasp, Stinger and Phoenix Hawk because I really don't think those would work in MWO, which only allows AeroSpace fighters to be used as strafe bombers, the LAMs would break the game in so, so many was so as to not be funny in the least, considering the game is still unbelievably broken in so many other ways.
As for the IIC versions of the Dougram and Macross mechs... Well... Let's see.
Griffin
The IIC 1, 2 and 5 work right from the get-go, with the IIC 4 being next up, but mounting ATMs, and we don't know how PGI will implement those, just like those Rocket Launchers on some of the Phoenix versions of the Macross based mechs.
Locust
The IIC 1, 2, 3, 6 and 8 versions work, with the 5 and 6 being iffy. The 5 mounts ATMs and the 6 mounts Machine Gun Arrays... But we can already do that as it is so actually there's nothing wrong with the Locust IIC 6.
Marauder
The IIC 1, 6 and 8 work, with the 3 coming in next, mounting ATMs, followed by the 2 mounting Heavy Lasers.
Phoenix Hawk
The IIC 1, 2 and 7 work, the 4 comes in next with ATMs, followed by the 3 with Heavy Lasers.
Rifleman
The IIC 1, 2 and 5 work, followed by the 4, mounting ATMs, and then the 3 and 7, mounting Heavy Lasers each, but the Plasma Cannons on the 7... No idea how those would work in MWO.
Shadow Hawk
The IIC 1 and 2 are the only ones that work straight up, the 4 and 7 come up next with ATMs, and then the 3 and 8 mounting Heavy and Micro lasers.
And finally...
Warhammer
Only the IIC 1 and 2 work right off, followed by the 4 and 7 with ATMs... The rest of the Warhammer IICs I don't even know.
PGI would have their work cut out for them if they were to bring in the IIC versions of the Dougram and Macross mechs.
Also, wow, that's got to be the biggest post I've ever done.