in your case inactive dont exist like attribute. So you can create it or use IIQDisabled attribute.
IIQDisable attribute is the attribute of sailpoint for checking the status of an account.
Also, I think your it won’t work as you want.
You can set a field like identity type, not as a link. So, the filter string work on identity attribute.
You have two way:
The first is mapping the userAccountControl of ad like identity attribute and use something like this without rule/script: <Field displayName="Manager" filterString="statusinactive== "false" && adActive == "false"" name="manager" type="sailpoint.object.Identity"/>
with this you a list of identity.
The second is create a filed like string and multivalued with an AllowedValuesDefinition rule. In this rule you need to build a queryoption with a filter on statusinactive, application and iiqDisabled:
and populate the field with the result of iterator.