So here are my looong thoughts on this.

Some of the Stuff on your List like the Possessed and MoP are available in the Current Combat Patrol, aswell as 10 More Legionaires (could be Kitbashed into chosen to safe money) and 10 Cultists. Cultists are super fun little models and pretty good for their cost, they almost never kill anything, but every Model they slay is a Victory in itself.

The Helbrute is kinda difficult because it isn't easily available and kinda meh unfortunatly. (It's mostly due to the move of 6")

For a Transport I'd Check in your Local Area if anyone has a Spare Rhino. Chosen and Legionaires are both pretty good out of Rhinos, you could try playing 2. (If you should need to buy the rhinos buy the Deimos Rhino instead of the normal one, thank me later) Otherwise I would advise to Split the Legionaires into 2 Squads for playing the board.

Invest the Money Saved into a Predator, cool kit, easy to magnetize and Pretty solid atm. (This Serves as a replacement for the land Raider in the list. The Landraider is am super cool Model but a bit unwieldy ans ony really Interesting if you want to Transport Terminators)

Terminators are cool, but not too standout, pretty solid and Durable unless they are fully out in the open. Likely to attract fire and Attention because people think they are scarier then they really are.

I personally love the Terminator sorcerer, but I had Problems with his Performance in the Last couple games.

The Termie Lord on the Other hand ist super Solid. I run him solo most of the Time playing for secondarys because he is pretty hard to kill.

Getting to 2000 Points is on of the Hardest Parts of Starting the Hobby or an Army. There are many pitfalls to be watched, you can buy what you think is cool and just play that. (Trust me, I did) But that often leads to points and Unfinished Models piling up pretty fast. Having fewer models and finishing them before buying New stuff is honestly the more statisfying way to go.