Generally accepted that Thousand Sons are too expensive for what they do because you pay for a sorcerer and power...
Deamon Weapon counts as a two handed weapon, so your lord cannot take a deamon weapon and combi-weapon

I recommend Berzerks aswell or more plagues or some non-sonic noise marines
Give the
CSM squad an aspiring champion and power fist and check your points: your
CSM atm =/= 165 (with 150 points + 20
ML + 5 flamer = 175 points) You also need Icon of Chaos Glory...
Don't mix special weapons if you can avoid it - plague marines work best with 2 plasma rifles and a plasma pistol
Chaos Space Marines don't get storm bolters so the dread cannot have one
Erm, add to it: some heavy stuff...
Either a vindicator or obliterators or a predator
I like Chaos Space Marine Havocs for my armoured foot horde - they last longer against anti-tanks weapons
I know since you converted the models from
SM that they may not be changeable but terminators get free power weapons that don't hit on int 1

Deamon Prince gets to take a psychic power and wings which is useful
Give every unit an Icon that can take one
Chosen may also be helpful because they can infiltrate five special weapons - a horde vs. 5 flamer templates

or an imperial guard parking lot vs. 5 meltas

Please check all of your units' points costs because alot of them don't add up to what is written as being included... e.g. your plague marine load-out is only 181 points
Final point, others may disagree but you don't really have much anti-tank...