If the new design is, as others have said, a light Clan OmniMech available during the early Invasion era, there are literally two entire choices left - Fire Moth or Fire Falcon. Fire Moth is notoriously No Go in MWO and Tiy0s has relatively recently stated this has not changed - it simply does Bad Things to hit reg and there's no fixing that, nor is the team willing to make the Fire Moth not a Fire Moth to cram it into the limits of MWO.
So, Code: Fastboi is very likely the
Fire Falcon
I don't have access to TROs to knwo where all the hardpoints are, but the Fire Falcon Prime is a 5E2M, and if the art is anything to go by four of those E are clustered in the right arm. The Alpha and Bravo are Light Snipey Things nobody will like, AC/2 light 'Mechs are bleh, but the Charlie is a 3E/2M/4B. The Delta is the last timeline-appropriate (for MW5: Clans) variant in the MUL from what I can see, and it's 2E3M. So the thing overall seems to have enough hardpoints to get by for a 25-tonner. It's significantly faster than the Meth Linux at the same weight bracket, but it doesn't have Mad Hops the way the Linux does.
As for MWO-esque powercreepy variants, well, the Foxtrot continues the grand tradition of Foxtrot variants being super spammy, heh. 4B in each side torso for 8B total, and 2E in each arm for 4E total. Easy swap to 6E8B using the Prime right arm, which will doubtless be turned into a tiny little hell-gnawer with micro lasers and machine guns. Other variants have fewer total weapons and thus would need fancy quirkening to be worthwhile, which I doubt we'll see if they do the Foxtrot. And we all know they're gonna do the Foxtrot. Heh.