Hi Barbara,
Thanks again for your great ideas. For your reference, the feature request IDs are below.
CR-251762 - Change a data type on a custom field that could be compatible - such as, change a single-lined text field to a multiline text field.
CR-251763 - Change a parent item type - ie, instead of a Request being the item type that the field could be used with, to make it able to be used on all Cases.