Welcome to the wonderful world of oils!
Watercolor is a whole different animal. If you are used to watercolors, you will definitely want to spend some time playing around with your new oils to get used to the feel of them.
I think you made a really good choice with the Lukas 1862 oils. As you said, they are not top of the line, but they are a good quality artists' paint and you won't be struggling with poor quality materials.
In watercolor you work light to dark, gradually building up the darks. Plus, once you lay down a color it's pretty much there for good and it's much harder to correct mistakes in watercolor. Oils are just the opposite. In oils one generally works from dark to light, and they are one of the most forgiving mediums. If you make a mistake, just scrape off and paint again! I'm sure you will come to love the juicy think lights you can layer on with oil paints. Keep your darks thinner and more translucent...that helps create a sense of depth in oils.
One thing I highly recommend...Once you've had some practice, paint on a surface that is primed with oil primer. You can purchase canvas and panels at Jerry's or Blick that are oil primed, but the most economic way is to use Gamblin's Oil Ground and prime them yourself. Just use it to go over a canvas or canvas board that already has acrylic gesso on it and you'll be good to go.
You certainly don't need to buy genuine cadmiums if you don't want to spend the money, but they do have a wonderful quality. The Lukas prices are great for genuine cadmiums. As a basic palette to start with I would recommend a warm and cool of each primary, one tubed version of each secondary, and then a few earths tones to round things out. Here is a list that I would say is good for the Lukas 1862 colors (this is only
Cadmium Red Light or Lukas Red (warm red)
Magenta Primary (cool red)
Cadmium Orange or Permanent Orange
Cadmium Yellow Lemon or Lemon Yellow (cool yellow)
Cadmium Yellow or Permanent Yellow Deep (warm yellow)
Phthalo Blue (warm blue)
Ultramarine (cool blue)
Cobalt Violet Hue (Dioxazine Violet)
Titanium-Zinc or "Mixed" White. Lukas doesn't make a mixed white, and I would avoid straight Titanium or Zinc by themselves. I highly recommend Winsor & Newton's "Flake White Hue" on this one. I think this is a good list of colors to start with. It's always best to start with the highest chroma (saturated) color you can get. You can always tone them down, but it's impossible to make a dull (low chroma) color brighter.
Also avoid using Alizarin Crimson. A lot of painters still swear by that color, but it's not permanent and will fade easily. A much more lightfast and nearly identical color is Rembrandt's Permanent Madder Deep.
Have fun and I hope this helps!!