Yep you sure can use the halide pendant. I use them on mine. You will need to change the Halide bulb itself if it's above 10000 kelvin as its not suitable for plants, and the blue tubes themselves unless you want to use them as night light. On their own they'll do nothing for plant growth.
The halide bulb can be anything up to about 10000kelvin.
I've a spare sylvania 6000k halide that will fit if you want it.
Co2 wise, if your going pressurised your best and cheapest option would be to buy a Seperate regulator, plenty of these on the sponsors sites, then look for a fire extinguisher or co2 cylinder online and get it filled locally. It's very simple once you've got the bits together and much cheaper than going all out on a full kit.
Plant wise just have a look on google at amazon plants or amazon set ups for inspiration. Also if your going co2 and halide, it will be beneficial to get either an all in one plant food mix or the ei mix from one of the sponsors also.
Hope this helps a little.
Good luck with coming to the green side and welcome to ukaps.
Edited: as per the Clive, I should really have said you may want to change it as you'll have a tank full of blue looking plants lol