Isovaleric acid is one of those flavors where we have MAJOR threshold differences. It cannot be tasted at all by a good chunk of the population (me included). I was at a Siebel off tasting seminar, and when they brought that out, most folks were making the nasty foul-taste face, while others of us happily drank away like it wasn't there (because to us, it wasn't).
I usually get DMS as vegetal, more like boiled cabbage, and occasionally like shellfish (clams or oysters). Sulphur comes across to me like farts or rotten eggs, but it will often dissipate if I swirl the glass.
Lots of lagers tend to display multiple symptoms simultaneously. This is usually due to weak fermentation -- lack of cell count and/or not enough nutrients or O2. I don't know how the new move towards lo oxygen affects beers. I assume the idea there is don't add o2 and really boost cell count so no cell growth is required.
If you want to send me a bottle, I'd be happy to see if I can help diagnose it for you.
PM me.