Look, there are plasma weapons (the plasma rifle and plasma gun) in Battletech, both of which, ironically, are LESS plasma weapons than the PPC. The plasma rifle fires basically chunks of superheated foam crap, and the plasma gun is sort of a flamethrower deal (I forget its actual name.)
The CCAF's Plasma Rifle has the damage of a PPC, with the added benefit that it also raises the target's heat by 1-6 (or just roasts the hell out of infantry). The downside is it only has the range of a Large Laser, and it has the unfortunate necessity for ammo supply.
The Clan "plasma cannon" is basically a long-range heavy flamer, also reliant on ammo. It can roast infantry, but the burning foam won't do much to a target Mech besides increase its heat scale (but up to 12 added heat on an opponent is nothing to scoff at).
And about the names: Personally, I use what I think is the more iconic name for each Mech, or failing that, whatever name causes the least confusion. (My RP character has a reason for this stance; me, I'm just bored.)
* My use of the name
Hellhound refers solely to the 50-ton Omni seen in MW4:Mercs, so that the second-liner can unequivocally be called the
Conjurer. (Incidentally, the latter was supposed to have once been the
Wolverine IIC, but was renamed for
obvious reasons.)
* There are two mechs which could be called the
Viper. Rather than confuse people, I don't use that name at all. I use
Dragonfly for the 40-ton Omni (it fits better anyway) and
Black Python for the 75-ton second-liner.
*
Mad Cat is shorter than
Timber Wolf. Not to mention there are the Clan spinoff designs based on it which don't even bother using the
Timber Wolf name. (Mad Cat Mk2, anyone? That's not an IS callsign, that's actually what the Diamond Sharks named it.)
* Because I'm already using
Mad Cat,
Mad Dog seems kinda redundant. Not to mention there's also an unrelated
War Dog.
Vulture it is, just for ease of differentiation, and because the Mech itself looks much more birdlike than like a canine of any kind.
* Because I didn't play Ghost Bear's Legacy, I don't think of the 3055 Clan mechs with their Clan designations. The only exception is
Goshawk, which I have no idea how I should pronounce (gaw-shawk? go-shock? goss-hawk?

) so I stick with
Vapor Eagle. Oh, and the above examples of the
Black Python and
Conjurer.
* I
did play standard MW2, so these Mechs are forever etched into my consciousness with their Clan names:
Firemoth, Kit Fox, Nova, Stormcrow, Gargoyle, Warhawk, and
Dire Wolf. In the case of the
Nova, I use its IS designation
Black Hawk solely to refer to the 60-ton Kurita knockoff.
*
Thor,
Loki,
Koshi, and
Fenris are shorter than
Summoner,
Hellbringer,
Mist Lynx, and
Ice Ferret, the last of which sounds much less menacing than its IS name anyway.
* The 95-ton Omni will forever be a
Gladiator to me, simply because I saw too damn many poptarting Gladbags in MW4:Mercs. I know there's also a Kurita 55-tonner. But it's so old and rare as to not matter much to me, apart from Keller's custom retool.
* Finally, both
Adder and
Puma work as far as I'm concerned, but I'll stick with
Adder because there is also a Star League
Puma assault tank. And the mech was made by the Star Adders anyway, so it fits better.
So yeah, I'm done.