I think oils get a bad rap and it's worth clarifying some things here. First of all, I don't consider oil painting any messier than other painting; if you want to see "messy" watch my kids doing watercolor! Much of that comes to personal style and/or technique which is equally true of nearly every art medium.
Solvents are another issue. I avoid them. They are unnecessary, especially if you make your own paints and understand how they work. It is true that you'll probably need more brushes in that case, or you can mostly apply with palette knives like some people do and then just wipe them off with a rag. The solvents become necessary because: 1) some commercial paints contain nasty stuff -- driers, solvents, additives -- in order to make the paint perform uniformly from color to color, but naturally the individual pigments would have different characters (I bet you see that in watercolors as well). 2) Some artists prefer certain working properties and/or fast drying that are unachievable with commercially available oils. 3) Some artists have wanted to incorporate resins into their paint which requires a solvent. All use of solvents are not bad, but most of it is unnecessary. If you start out making paints yourself and avoiding solvents completely, you won't fall into bad habits you need to break later!
Pigments in oil paints (all paints, really) can be quite poisonous as well. If you are careful you could use them, but you need to be careful. I don't want to be handling cadmium or lead dust, especially in a home with children. But, there are a lot of less-toxic options (I'm not going to call any of these non-toxic, but I don't mind handling iron oxide or dirt or rocks).
The oils themselves are also an important discussion. I strongly recommend you start with oil you can trust, probably that you've tested, preferably linseed. Safflower and sunflower are marginal driers and are likely to not make a stable paint film. I've read that it might come down to the growing conditions and specific varieties whether it ever dries. Walnut oil is a slow dryer but makes a reliable paint film if you're patient (but it might be a few weeks between layers). Linseed is the classic, but commercially refined oils tend to yellow and be relatively slower drying than hand-refined oil. The "dark horse" is hemp oil which seems to be between linseed and walnut in drying, reliably non-yellowing and with interesting properties (but not a long pedigree in art conservation, so unknowns in the long run). The earth pigments will likely help the paint dry more quickly, but the mineral pigments may or may not.
I could rant on and on about all of this. It's not necessary (or even necessarily useful) to control the entire process from start to finish. It depends on personal preference. I like it because there is so much to learn, and in the end, I think I like the learning even more than the making of the art. It also forces one to slow down, which is the opposite of many "mainstream" and "working" artists today -- a luxury a hobbyist with a day job can have! If your oil might be aged for 6 months to 2 years or more, your dyestuff for pigment might take 2-3 years just to grow to maturity, etc., that makes a week's drying time between layers to be completely within reason. But, again, that's my own approach and not universally needed!