Your design hides messages that the user needs to complete their task - helper text and error text. The user needs immediate access to helper text to ensure that they complete each field correctly on their first try. They also need immediate access to the error text so they can correct invalid inputs.
I don't see the usefulness of having these messages hidden by default. Forcing the user to click a button to reveal error messages is a needless source of friction. I can't imagine a scenario in which the user would find it profitable to explicitly hide these messages themselves.
The error toggle button is not a standard convention so the user will be less likely to click it. Additionally, it does not look like a button and the label ! does not communicate its functionality.
Successful validation notification
While this is commonly used for login flows, I don't see this in use for general form inputs. As Pushkar has already pointed out just skip to the next field when validation is successful. These micro-validations are of interest to your backend system but they are not that important to the user. Signalling that each field is validated when the user just wants to submit the form is unnecessary in my opinion. Additionally, validation and errors should only show after the user has provided an input.
Disabling the helper text icon indicates that the function is unavailable when you are really attempting to indicate the absence of this functionality. If helper text is unavailable for a field I would remove the icon. Similarly, if you don't perform data validation on a field then no validation controls should be given.
- The error message should be immediately visible after an error has been found. The error button ! should be converted to an icon since the message toggling functionality should not be needed. It serves your accessibility requirements so there is no need to remove the icon.
- Consider showing the helper text below the question by default. This way the helper text will always be visible to the user while they complete the field. Also, remove the helper button/icon ? as it would only add visual noise to the form if the helper text is already immediately visible.
- Validation icons can be removed or at most shown temporarily when an error has been resolved. If kept, validation icons should only be shown in response to a validation performed. Questions that have not been answered should not have a validation icon.
Suggested design before form input and validation. Helper text below field title is immediately visible, there are no validation icons and optional and required fields distinguished only by *.
Suggested design after validation performed with error message and helper text immediately visible.