Yes, it should do the trick. I did submissions to the foreign directories etc. and I found that is works pretty fine. So can't say something bad, just good experience
Every link will help BUT the main aspect for their value is still the trust of the site the link is comming from. If you have established german or french sites linking you this can be worth as much as a english link I guess
I don't think it will help a lot. IT is better to make links on websites in the same language and the same niche.
They won't be useful for particular keywords' positions but will helpful to the site itself - if the donor is trusted.