escalation campaigns

hi guys, hope we are all well?

i'm playing in an escalation campaign as the dark kin soon and i've done a few test games.

opponents are:
-necrons
-tau
-space marines (codex)
-imperial guard

so far i've played a test 750 list against guard and necrons, sealing me a win (very cagey boring game) and a draw (by the skin of my teeth!)
with variations on the following:

heamy, VB (+/- liquifier)

x10 warriors, cannon
raider

x10 warriors, cannon
raider

x9 wyches, heka, aggy
raider (+/- AE sails)

x6 Jbikes, x2 heat lances

so there are a couple of rules that are confounding my choices here.
whatever i start the campaign with must remain in my army in some form. they can be enlarged or shrunk, take different options/equipment but must remain in there in some shape.
we only have x1 slot at the start for Elites OR Heavy support OR Fast attack.
extra slots will be earned by building manufactorums on tiles we capture in the campaign.

the bulk of my troops i'm happy with, they perform ok.
i'm not happy with the heamy, he's just too squishy and gives away "slay the warlord" point left right and centre.
i'm not entirely happy with the reavers, they're expensive and havent perorm as well in a multi-role as i'd hoped they would.
they've not been great in combat and are yet to hurt any tanks with their heat lances. i took them as they're versatile on paper, but it'll mean that i have 2 fast attack slots when i get my first manufactorum, yet i dont plan on using my scourges or 2nd reaver unit early in the campaign.

i have some elites: x4 incubi, x5 dakka born, x5 blasterborn that could take that slot.
likewise i have some heavy choices: x2 ravager, razorwing, chronos (flyers are out until a spaceport is captured/built)

as it stands, i'm tmpted to take the ravager, though the 2nd slot might end up being wasted when i ear it as people are quite infantry heavy in this campaign.

as for the HQ conundrum, i have a succubi and an archon to swap him out for, though i suspect an archon would be a bit expensive for 750 pts.
what would my fellow archons do in this situation?