From what I see, they make up a range of demographics and educational levels.
As to why they did not bring their families over in the first place? That is usually because they want to make sure they have somewhere to stay before bringing their families over.
Bigger picture. The population of Europe as a whole is 740 million or so. Even if the entire population of Syrian pitched up in Europe (20 million or so), it would be under 5% of the population. The actual numbers of refugees is around 5 million, so less than 1%. You are trying to suggest that 1% of the population is a "demographic shock"?
The problem arises when the refugees are concentrated in a few countries, and then other nations use the crowding and chaos there as an excuse not to take any.
"Men without solid economic recourse", as per my previous point, these individuals span the entire socio-economic range, and have a wide range of skills. If they are able to gain employment (Many countries do not allow refugees to work) then I do not see why they would not have solid economic recourse.