My first thought is that the 'local shop' offering you this deal is an Atomic dealer.
And, there is nothing wrong with that. For the record, so is the shop where I teach.
Ordinarily, I would suggest that you slow down, take a breath, and try out some different gear before plunking down $2500 for what you listed. But, if you are h***-bent on buying gear right now, I will go along with tbone and Jim Lapenta for the most part.
You are diving in SoCal, with colder water, and consequently a need for thicker / more buoyant exposure suits. Even if you are inherently neutrally buoyant, you really don't want to add more of a lead burden by going with a positively buoyant, 'floaty', fabric BCD (e.g. the Knighthawk). Nothing really
wrong with that BCD, it just isn't an optimal unit for the environment you describe. You would be better served with a steel backplate, which will a) put the weight where you actually want it - adjacent to your physiologic center of lift (lungs), and not on your waist (in integrated pockets) where it will pull your legs down, and b) will reduce that 24 pounds of lead the LDS wants to sell you, to something far more reasonable, and appropriate. Since you are in the area, I echo the suggestion to give Deep Sea Supply a call. It can't hurt, and you will quite possibly find a very helpful - and knowledgeable - vendor.
I would NOT go with a console-mounted (air-integrated) computer like the Cobra 3. Go with a wrist unit (you will NOT regret that decision), and hold off for now on air integration.
I like the Dive Rite XT fins, and that suggestion is well worth considering. Personally, I find the foot pocket on the Atomic Blade Fins to be quite uncomfortable, in comparison to Dive Rites or Mares Quattros. That might just be me. But, having used all three, I also get the best performance from the XTs, with the Quattros a very close second. And, they both 'feel' good in the water.
The most important consideration in masks is fit. After that, you need to consider fit, and then, all else being equal, you should base you decision on fit. You may notice a theme here. I favor low volume masks, and don't really have an issue with single pane vs dual lens. If the Atomic mask really fits you, really well, go for it. One other option, that usually offers some surprises: ask the local shop to show you the cheapest mask they sell. After they get through telling you that price should not be a consideration, and the best mask for you is determined on the basis of fit (both of which are true), try on whatever is their least expensive mask, then try on the Atomic. See if you can tell a difference between that one and the Atomic, in terms of FIT. I say this because, for years, I have been diving a SeaDive Caribbean - the least expensive mask sold in both of the shops where I have worked. And, that mask fits me perfectly. You my not be so fortunate, but it is worth a try to ask about options. I really like the appearance of the Atomic masks we carry - very slick-looking. But, I have 3 SeaDive Carribbeans in my kit box (along with a rather expensive, large volume, single lens purge mask that I was talked into buying as a brand new diver years ago), and no Atomic masks, even though I could get them at a very favorable staff price.
Hold off on the weights for now. If you need to strap on 24 lbs, you can buy that later. I doubt that you will if you avoid the floaty BCD. Similarly, think about what you need a knife for. EMT shears work for just about any cutting you need. Put a pair of shears on your waist strap, and forget about strapping a pig sticker to your thigh.