1. http://www.ncbi.nlm.nih.gov/pubmed/20679559
As has been mentioned by other posters, this study demonstrated that carbohydrate restriction was as effective as extreme calorie restriction (as low as 1200kcal/d!) in causing weight loss. Carbohydrate restriction was better at improving just about every indicator of cardiovascular health that exists--triglyceride levels, HDL levels, blood pressure, etc.
The abstract for this study supports the assertion that carbohydrate restriction is an effective and healthy weight loss technique. It does support the assertion that starving yourself can also promote weight loss; I do not believe anyone here has disagreed with this hypothesis, however. (I would argue that few people will willingly remain on a 1200 kcal/day diet for the rest of their life, however.)
2. http://www.ncbi.nlm.nih.gov/pubmed/20663066
This study is dealing with low glycemic index diets, not low-carb diets. It is largely irrelevant to the discussion. (Note that frucose, a carbohydrate, has a very low glycemic index.)
3. http://www.ncbi.nlm.nih.gov/pubmed/20670466
This study deals with monounsaturated fatty acids (MUFA), not carbohydrate-restricted diets in general. I note also that the "high fat" diet in this study only included 35-45% of calories from fat, and about 45% of calories from carbohydrates. In other words, this study does not appear to contain any low-carbohydrate diets, and is again irrelevant to the discussion.
4. http://www.ncbi.nlm.nih.gov/pubmed/20571327
This study appears to concern the use of the drug orlistat for weight maintenance following weight loss.
Orlistat: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000175
Leaving aside the rather scary warnings about liver damage, it appears that orlistat is used in conjunction with "an individualized low-calorie, low-fat diet".
This paper does not appear to have any relevance to a discussion of carbohydrate-restricted diets. (Except, perhaps, as an argument for the scary side effects of the alternatives.)
5. The link for this is wrong. This appears to be the right one: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2125573/
The "final nail" in the coffin of carbohydrate restriction, as you put it, appears to be a study comparing a fat-restricted/calorie-unrestricted diet with a calorie-restricted diet. Carbohydrate-restricted diets do not make an appearance.
End result: Four irrelevant studies, one which supports carbohydrate restriction as a superior alternative to calorie restriction for weight loss and cardiovascular health.