Move into another table or not?
I think they should stay on the same table ! 
 If you have lots of row(questions) you can use this column(type) to partition your table by it as i think you might have 3-4 distinct values(select,text,checkbox) !

 This would make your query faster by doing this !

  As for the naming of your type column, yes they look better as number and save you some space on you database as Int comparisons are faster than varchar comparisons, for the simple fact that ints take up much less space than varchars.