On the Pachypodium question ...
Some Pachypodiums are easy to grow from seed (eg. lamerei), and this probably has to with how common they are in cultivation. Some have a reputation of being a little more finicky (eg. brevicaule), and this probably accounts for their relative rarity (and higher price for mature specimens). I have grown both of those species from seed (those are the only Pachypodiums here that have ever produced fruit). One species I would explicit recommend you avoid is namaquanum, which is a winter grower and pretty much guaranteed to melt down with lots of summer rainfall.
My lamereis grew out pretty fast. The seed is big, germination was good, you will have a pretty good sized plant in a year or two. They respond well to typical succulent seedling care.
Be aware that your seedlings will at some point lose their leaves and want to take a nap, for at least a few weeks out of the year, once they reach a certain age of months or years. When this happens (as with any mature Pachypodium, only a couple of exceptions), you should back off on the water. For me the difference in frequency with leafy vs. leafless Pachypodiums is typically 2-4 fold, depending on the situation. Dormancy is more evident (and longer lasting) in temperate climates.
Curiously, 25% of my lamerei seedlings were crested, which was very interesting to me. Anyway, strange things happen early in life with these plants. Some (many) lamereis branch early in life (ie. before they flower) and these are more desirable. Some of that is genetics and some of it is a roll of the dice.
My experience with P. brevicaule was great until maybe 6 months of age, when I allowed the soil to go too dry for too long and my seedlings all melted down in unison. I have read this is thing to avoid with brevicaule (very young seedlings, older plants when they are in leaf). Fine line there between underwatering and overwatering with these plants, this is where the tricky part seems to be. Good drainage improves your odds if you are a generous waterer (or the plants are exposed to rain).
Anyway, the seeds for brevicaule are a fraction the size of the ones for lamerei, and the young seedlings are correspondingly smaller and slower as a result. I took a picture of the two seeds side by side back in the day but I haven't been able to locate it.
Strong light is important not just for health and disease resistance, but also for the development of a compact form. Taller is not necessarily better with Pachypodiums (in my very opinionated view). You will thank yourself for paying attention to this aspect when your plants grow up.
