Saving boolean instance variables

so I have 11 instances of an object on the scene, each one has a different instance variable.

1 (as a string),
1 (as a number),
1 (as boolean),
true (as a string) and
true (as boolean)
the same?

So how can I save them in a storage and which variable type should I use?

no, you can not save objects directly.
what you can do is, write each object into a Variable structure and then save the structure as json.
have a look at this;

or download my advanced shape painter example and have a look at the structure system:

you can also have a look at the level editor example in GD.

It might be wise to just use scene variables directly, instead of object variables, depending on how you use them. If you can use scene or global variables for the same purpose you don’t need to have them twice.