This is what I came up with given what you have available:
1st Company: (BV2: 13,313, PV: 328)
Pursuit Lance:
Trebuchet TBT-5N,
Javelin JVN-10N,
Commando COM-2D,
Commando COM-2D
Battle Lance:
Black Knight BL7-KNT,
War Dog WR-DG-02-FC,
Hunchback HBK-4G,
Blackjack BJ-1
Command Lance:
Cyclops CP-11-A,
Orion ON1-M,
Huron Warrior HUR-WO-R4L,
Raven RVN-3L
2nd Company: (BV2: 12,730, PV: 335)
Pursuit Lance:
Marshal MHL-2L,
Assassin ASN-21,
Javelin JVN-10N,
Tarantula ZPH-1A
Battle Lance:
Grasshopper GHR-5J,
Thunder THR-1L,
Hunchback HBK-4G,
Blackjack BJ-1
Fire Lance:
Catapult CPLT-C4,
Blackjack BJ-2,
Vindicator VND-3L,
Whitworth WTH-1
3rd Company: (BV2: 12,705, PV: 334)
Pursuit Lance:
Assassin ASN-21,
Cicada CDA-2A,
Vulcan VL-2T,
Javelin JVN-10N
Battle Lance:
Orion ON1-K,
Cataphract CTF-2X,
Hunchback HBK-4G,
Hunchback HBK-4P
Fire Lance:
Longbow LGB-7Q,
Catapult CPLT-C1,
JagerMech JM6-S,
Trebuchet TBT-5N
Here's my thought process behind this arrangement:
First, I start with a few rules:
* I conform to the formation rules in Alpha Strike Companion and/or Campaign Operations if at all possible.
* Every company must be relatively self sufficient. This means each company should, if possible, have a pursuit or recon lance, an assault or battle lance, and either a cavalry or fire lance. A command lance may take the place of any of these.
I created a spreadsheet of all of the 'Mechs and their Alpha Strike statistics. Even if you plan on playing using Total Warfare instead, I believe balancing using the Alpha Strike statistics will get you most of the way there.
Under the formation rules, each lance time has to conform to certain rules.
* Battle lance: 2 'Mechs (50%) must be heavy or larger. At least 3 'Mechs must have the Brawler, Sniper, and/or Skirmisher roles.
* Command lance: 2 'Mechs (50%) must have the Sniper, Missile Boat, Skirmisher, and/or Juggernaut roles and at least one 'Mech has to have the Brawler, Striker, or Scout role.
* Fire lance: 3 'Mechs (75%) must have the Missile Boat and/or Sniper roles.
* Pursuit lance: All 'Mechs must be small or medium. 3 'Mechs (75%) must have a move of at least 12" (TW: walking MP 6 or higher) and at least 1 'Mech must have a Medium-range attack value over 1 point (TW: at least 1 'Mech must have a weapon that can deal 5+ damage at a range of 15 hexes or more).
Looking at the list of 'Mechs, I see there are 'Mechs that have obvious places to be. The
Hunchbacks will all go in battle lances. The 'Mechs that move at least 12" (6 walk MP) will go in pursuit lances (although I might move the
Raven later.). The
Longbow and
JagerMech will go in a fire lance. Somewhat arbitrarily, I decide the
Cyclops is probably the CO's 'Mech and it will go in the command lance. (The
Cyclops is fluffed as being a command 'Mech.)
To satisfy the requirements for battle lances, I have to assign 2 heavy 'Mechs to each lance. Excluding the
Catapults, there are 7 heavy 'Mechs so this should be easy. I'll hold back the
Orion ON1-M for the moment. The ON1-M mounts an LB-X autocannon and would probably go well with any holes opened up with a Gauss rifle, which would be the
War Dog,
Huron Warrior or the CO's
Cyclops.
Most of the remaining 'Mechs have a Long-range attack value of at least 2 so I believe they'd be reasonable members of fire lances. The only exceptions are the BJ-1
Blackjacks and the
Marshal. I put the BJ-1
Blackjacks in the open spots in the battle lances and the
Marshal into the current open spot in a pursuit lance. The
Marshal is slower than I would like for a pursuit lance but it might be able to keep up in broken terrain since it has a jumping move of 8" (TW: jumping MP of 4).
The
Raven is the one 'Mech that has an Active Probe. I figure the CO is probably paranoid of ambushes so he'd want to keep it close. That opens up a spot in a pursuit lance that I grudgingly fill with a
Trebuchet. It'll slow down the lance but it'll probably have more firepower than anything they encounter. (Another option would be to assign the
Huron Warrior but I have a plan for that.)
I assign the
Huron Warrior and the
Orion ON1-M to the command lance to fill it out. Both are decent long range fighters and, if the
Orion closes, it should be able to exploit any holes opened by the Gauss rifles. Admittedly, the
Orion's Narc beacon will probably go unused but it's more a deterrent than an active weapon.
This leaves six 'Mechs. Of these, five jump for 8" (TW: jumping MP of 4). I group four of these (the
Blackjack BJ-2.
Vindicator,
Whitworth, and
Catapult CPLT-C4) and make a lance. The two remaining 'Mechs, the last
Trebuchet and the
Catapult CPLT-C1, join the
Longbow and
JagerMech.
That takes care of all of the 'Mechs.
If I had the option, I would replace one of the
Hunchbacks and one of the
Trebuchets with 5/8/5 (or faster) 'Mechs for better fits in the pursuit lances. (This would move the
Marshal into a battle lance.) Looking solely the RATs in
Field Manual: Periphery, the the
Dervish DV-6M looks like the one reasonable option. Using the MUL opens up more options, even if keeping the tech level the same, including the
Phoenix Hawk PXH-1,
Griffin GRF-1N, and the
Enforcer ENF-4R.
If I made that change, I would also consider replacing a heavy 'Mech with one that jumps (I'm partial to the
Guillotine) and then rearranging the 2nd company so every 'Mech in it could jump. This company should then excel in broken terrain against forces that aren't equipped similarly.
If you would like to explore other options,
take a look at the MUL to see what the Magistracy would have available.