Hmmm.
OK, well, a few thoughts on the lances...
A: Defiance is a tough customer, no doubt. The TRO version (I don't have the book handy to look up the designation) is twin PPCs and an LB-10X backed by a few light weapons, and that's as good of a combo as you'll find on a heavy. I dig it. Hunchbacks... the 7R is one I'm not a fan of. The CASE II is nice, but the Ultra 10 isn't really a good weapon as a focal point on a design. Now, the 5S? LB-20X means never having to say you're sorry, I like this one a lot. The 5SS (I think that's the one?) packs a big wad of MML launchers instead of the cannon, that's pretty fun too. Oh, or the 5SG (?), which gives you a sniper that has a Gauss rifle and stealth armor, because your enemy deserves to cry a little. And of course, the Commando is a stalwart little beast- yours jumps, to boot, which is always fun. I like the lance overall, but if you can drop that HBK-7R for a better version you'll be in better shape.
B: Same Hunchie, same problem. LRM carriers are beefy in terms of long-range power, but with only eight points of armor per location a couple of hits wipes them out fast. The enemy's best bet then is to run up at them where their weapons work, and the LRMs don't. A good bodyguard unit is effective here- like, say, a Hunchback, how convenient! But where an opponent might think twice about entering an AC-20s range, an Ultra-10 just doesn't scare most players enough (I know I'd risk it!). The Scorpion's addition to your force is negligible, honestly. Not a fan of this lance- a couple of quick enemy shots and you're down both LRM carriers.
C: Same issues as B, but the Commando is a better choice than the Scorpion. Better, but still not one I'd want to use given other options.
D: Well now! The Ontos is always a pain in the ass to deal with as an opponent. The LRMs give it a little extra muscle at range, but in close those lasers are just... eugh, it hurts. I suggest the 3058 upgrade if you can over the original from 3039- losing one laser to gain pulse to three of the remainder is a good upgrade, and the added SRM beef gives you some crit seeking power to boot. Same bad Hunchie, but here the Scorpions make a little more sense working as long range support while your giant waddles into range. You're vulnerable to motive hits stopping the monster in its tracks, but that might be worth the risk.
E: The guy who sold you that Hunchback must be happy. ;) Same as D, but the Behemoth is a very different force of nature- there's two major variants, both of which you'll find in TRO:3145's Liao PDF. One is a bit conventional, with a Gauss rifle, an ER large laser, a couple of Streak-4s, and a couple of LRM-20s. The other though is an oddball that trades out much of that loadout for a few rocket launcher packs and EIGHT Thunderbolt-5s. It's an odd duck of a tank, but scary as hell- I'd take it over the Ontos, personally, but both have a lot of power in different ways.
Honestly I'd go with A, given a choice, but... really, that HBK-7R is a lemon, find a better Hunchie.