Hi Gunilla,
Humm, this has to do with the nature of each specific question type. Lesson is looking for the correct answer.
Take a close look at your multiple choice questions that work. All answers go to the next page. Students get to make one choice, all choices are correct because they go to the next page.
I tried a short answer in demo.moodle.org. I left all answers blank. The continue button appeared because there was no answer for it to evaluate. Since you want the student to attempt an answer, you need to put a wildcard "*" in the first answer and double check that it is sending the student to the next page.
I believe issue for a numeric and a multi answer question is that there is no way to accept all possible answers as correct. At the moment there is not a wild card you can put in the first answer of a numeric question (like I suggested for the short answer question) that will select all answers as being correct. My suggestion is to use the short answer as if it were a numeric and see how that works.
In the case of a multi answer question, it is the logic in the question type itself. This is hard for me to explain. The student either gets the question completely right or get the question completely wrong in this type of Lesson question. This is not obvious to the teacher but is the way it works in the Lesson module. So if you set all the answers to this page, any and all answers would be wrong. If you set all answers to next page, then the student would have to select all the answers to get the question correct. I don't have a suggestion on how to work around this problem.
I believe Quiz questions handle things differently. You can give credit for a wrong answer in multi answer question and you can use a wild card in a numeric question.
I hope this helps. It was a simple question but a many layered answer
Chris