It matters a little but not as much as you may think.
(By the way nothing says the dividend has to be yearly, as a company you can pay multiple dividends a year if you so choose. It's more paperwork, and probably costs more in time from his accountant but otherwise you can do it as far as I know.)
Onto the two points,
1) The Social security is based on their wage, and no arrangement with the employers bookkeeping is needed. Their full time job would likely be Tax Class 1 (Or 3 if married) and the second job would be Tax Class 6. If there did happen to be a discrepancy it would likely be small, and paid back when they do their tax return. I also think that the Geschäftsführer of a company doesn't pay social security (or maybe pays a reduced amount?), but I might be wrong on that bit.
2) Yeah he/she must inform their boss, but unless they directly compete with the company, or the side business would affect their job performance they don't really have a valid reason to say no.
My suggestion would be to form a UG, they're relatively cheap and would be easier than the hassle of a foreign company. A foreign company whose operations are based completely within Germany would be liable to pay tax in Germany anyway.
I've heard http://firma.de are good with this sort of thing, and they have several articles on the different company forms in Germany to help. I am however in no way affiliated with them, and haven't used them myself yet.
(By the way nothing says the dividend has to be yearly, as a company you can pay multiple dividends a year if you so choose. It's more paperwork, and probably costs more in time from his accountant but otherwise you can do it as far as I know.)
Onto the two points, 1) The Social security is based on their wage, and no arrangement with the employers bookkeeping is needed. Their full time job would likely be Tax Class 1 (Or 3 if married) and the second job would be Tax Class 6. If there did happen to be a discrepancy it would likely be small, and paid back when they do their tax return. I also think that the Geschäftsführer of a company doesn't pay social security (or maybe pays a reduced amount?), but I might be wrong on that bit.
2) Yeah he/she must inform their boss, but unless they directly compete with the company, or the side business would affect their job performance they don't really have a valid reason to say no.
My suggestion would be to form a UG, they're relatively cheap and would be easier than the hassle of a foreign company. A foreign company whose operations are based completely within Germany would be liable to pay tax in Germany anyway.
I've heard http://firma.de are good with this sort of thing, and they have several articles on the different company forms in Germany to help. I am however in no way affiliated with them, and haven't used them myself yet.