Hey Mike,
Apologies if i pronounced your name incorrectly.
In answer to your questions:
1. Do both. The review on the site will bring in longtail traffic for the client and the link from the competition or secondary review will pass more authority back to your site.
2. That's a tricky one- what is the local language? In the first instance I would use advanced operators that alow content submissions or have communities around your product. FOr example: intitle:write for us "beauty" or use the wildcard to search for lists "top*Beauty Blogs [local place name]"
3.Why not contact a local beauty school and ask them to trial the product? Or sponsor a prize giving/ award ceremony/study group/sports team and get them to link back to your site.
4. This depends on the scenario, if you link is on a blogroll with 100 other links all using keywords to link then this is bad .But if your site is on a blogroll with a small amount of quality sites, this is fine.
Link Building is like your diet, everything is fine in moderation.