Q: (How) Can I list simple changes only for a given namespace?
A1: I can call the SimpleChanges and define a filter for a namespace and can include it in a wikipage.
A2: special pages allows me to add parameters like:
Special:RecentChanges/days=5,limit=40,hidebots,hideminor
... and if I want to add a namespace it would look like:
Special:SimpleChanges//days=5,limit=40,hidebots,hideminor,namespace=3000
So this seems to work - only that I had not any changes listed that meet the days and limit parameters ...
Note: I included those { { Special: ... }} when I added it to a page.