Hi, Marcel,
to answer your first question.
Please, read the chapter about question types in the manual.
www.limesurvey.org/manual/Question_types
These "predefined" question types like "5-point-scale" are -in my opinion - only used for other purposes using these settings
E.g. as a star rating scale
or this "Emoji" scale
To be free in the number and wording of answers you obviously have to use the "normal" question types, like list(radio)
or a "normal" array
And I do not understand your second question.
Either you resize your browser window or you use the webdevelopment tools in each browser to "fake" a mobile.
Joffm