There are probably added sugars in that one which would make it no good. We have several threads on here which discuss the merits of various yogurts. They might have dropped off the first page but have a look around for them.
The Onken is definitely out - all milk products have lactose (milk sugars) which can't be avoided, but the Onken has added fructose (fruit sugar) - which is one of the sugars which is most easily digested, and so causes a spike of blood sugar and insulin when you eat it.
The result a.) you come out of ketosis because the body will always use the blood sugar before it uses fat b.) any sugar it doesn't use will be stored as glycogen and water, ie - fat, c.) the blood sugar rush will be followed by a low, and you will feel ravenously hungry.
As a rule of thumb - be really suspicious of any product that describes itself as "Low fat" or "Fat Free" - because they are often loaded with starches and sugars to make up for the fat removed.
Good idea to check the action of lactose, as it has some good functions for dieters, hence the amount of dairy in Dukan. As long as there are no added sugars, all the dairy we r on will have approx 8%. and yogurt has healthy bacteria in too that assists the dreaded binding, promotes functions of good intestinal bacteria.
Up to u of course, but I think you should just get a better brand or make your own.
Don't avoid the natural sugars in milk entirely - they actually have a beneficial effect. They combine with fats in the gut into a sort of soapy substance, which makes the fat move through and out more quickly.
Just stick within the dairy limits set by the diet, and treat flavoured yogurts - even mullerlights - as special treats rather than daily staples.
The sugars to avoid above all other are fructose (fruit sugar), HFC (High fructose cornsyrup) glucose/dextrose (usually made from starches) and sucrose (table sugar).