The term "science" in English definitely does not include the humanities. There are ambiguous cases, where it is unclear how to draw the line between humanities and social sciences, but for example literature is never considered a science. If you wish to include the humanities, then you must use a broader term.
Social sciences are a little trickier. At one level, they are obviously sciences: it's even part of their name! On the other hand, people sometimes use the term "science" as shorthand for the hard sciences, without meaning to include the social sciences. This means you are welcome to use the term inclusively, but you shouldn't expect that it always includes the social sciences when you hear other people using it. If this distinction matters, then you'll need to discuss it explicitly.
It's worth noting that there are a lot of other things that don't fall under "science" in English, besides the humanities. For example, engineering has some overlap with science, but engineering fields are usually not classified by universities under the sciences, and references to science will not be understood to include engineering. (This is one reason the term STEM is popular: it's the shortest way to refer to both science and engineering in English.)
If so, is there an umbrella term describe everything from social science over STEM to law and what not?
Unfortunately, I don't think there is. (Maybe there are obscure terms out there, but there certainly isn't one that is widely used and understood.) You could use broad phrases like "all academic disciplines" if you really want to include everyone, but there is not a specific term like "science" for this.