So I was given a 2011 Specialized Sirrus a couple days ago for free. I just needs a tune up, bottom bracket maintenance, and new brake cables as is. Pretty good for free!

But I would like to work towards converting it from a flatbar hybrid to a drop bar road bike. I know that the geometry won't be the same as a real road bike, but it was free. Currently while riding it I feel as if the stem is too short such that handlebars are too close, but of course I'm also not used to sitting up on a bike. So I figure that considering drops reach farther forward it might help that problem as well.

this is my current parts list.

SRAM PG820 Bicycle Cassette 11-28 https://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER

ZEUS CAT II 46cm Alloy Drop Handlebars 31.8mm Aluminum Black 460mm https://www.amazon.com/gp/product/B00...A1J160NEEMK233

Problem Solvers Travel Agents https://www.amazon.com/gp/product/B00...A2TE9IQP68MWQU

Shimano Brake Cable and Housing Set (Universal) https://www.amazon.com/gp/product/B00...=AJ5KCH6R81QUN

Shimano ST-2303 3x8sp STI set, front/rear - sil/ https://www.amazon.com/gp/product/B00...A1T143F568NMY7

Total: $178.35

Is there anything I'm missing?
Also my derailleur is a shimano altus 7 speed I believe, will it still work with 8 speed shifters and cassette?
I'm trying to do this on a bit of a budget and of course the more it costs the longer it will take for me to get that money.

If you are going to swap out the (I assume) V-brakes for cantilevers, you are going to need cable hangers for the front and rear.

Doesn't the FDER have to also be changed to work with the new shifters?

You probably won't know about the bars until you do the conversion and see how the reach feels, but if the bars currently feel too close, drops may end up being in the neighborhood for you. I've done 3 such flat to drop conversions now. Each time is some experimentation with stems and handlebars until I get it feeling right.

I have V-brakes with Tektro RL-340 levers on two of them. On one the combo works just fine. That one has some cheap V-brakes that were robbed from a $20 donor bike. The other one has some nicer Tektro V-brakes and the rear is very finicky about everything needing to be in perfect adjustment. I did try some RL-520's, which are meant for V-brakes, but they weren't nearly as comfortable, and I'm a hood rider. I may change that bike out for cantis soon.

On the drivetrain, I just went with bar end friction shifters on all 3. No worries about needing all the parts matching.

It's a 3 speed FDER with 3x8 shifters, wouldn't it be alright?

Well would it be ideal to switch to cantilevers with hangers or get something to modify the V's?

I'd suggest that you get a new chain to go with your new cassette. A chain with significant mileage is likely to not play well with a new cassette. I prefer a chain with a quick joining link to the Shimano "special joining pin" concept.
A fork mounted cable hanger will help you to avoid brake shudder with your new cantilever brakes. Problem Solvers Wide Cable Carriers https://problemsolversbike.com/produc..._cable_carrier will ease adjustment and centering.

updated OP with new parts list

I'll look at getting a new chain possibly once I'm done with the conversion if it shows problems, I'll definitely look for a chain with a quick joining link. Oh, and I changed to using travel agents to modify my V's instead, thank you for the advice though.