3x Ordinatus Minoris
Quake cannons
Powerful... anything they see will be heavily damaged/destroyed... their slow speed will mean they can dominate one part of the board, but will struggle to attack other areas. Leave them as late as you can in the deployment phase so you can target your enemy's most suitable formation.
1x Demi Century
+ 1 Hydra,Tech lord,Anti tank support
I've never had much luck mixing infantry with tanks in the same formation, but I guess it could work... having on-board AA is very useful, though I'd be tempted to put it with the Ordinatus Minorii.
1x Demi Century
+ Anti tank support
Again, a solid-looking formation, but see my final summing up...
1x Demi Century
Fine.
1x Cataphract company
+ 1 Hydra, Vanquisher
Fine
2 Thunderbolts
Very fine!
Thoughts?
Here's my thoughts:
Your list, at 6 activations, is running a little low on numbers, all your formations are hard to kill, but they may struggle to manuever versus an enemy with 9 or more activations.
If you drop the two 'anti tank support' upgrades from your Demi-Centuries, you free up 400 points to spend on extra formations.
I'd go for either six Forge Knights (400pts), or three Hydras (150pts) and a formation of ten Praetorian Combat Servitor units (250pts). That would give you more formations to use, and your infantry could Garrison further up the board before the game begins as they've left the tanks behind.
I'd also move the Hydra with the Tech-Lord's Demi-Century to escort the Ordinatus Minorii, so as to help protect them from air-assaults.