Incident and workaround

the third level support group found a Workaround for the Incident. Following IT
Service Management Best Practice, what will the Service Desk do?
1. Record the details of the Workaround in the Incident record so that they are
available for review should the Incident occurs again.
2. Send the details of the Workaround to Problem Management for analysis.
3. Record the symptoms of the Incident and the details of the Workaround in the
Frequently Asked Questions so that users can understand what actions they
can take should this Incident affect their work.

Answer:
Your approach is quite correct. Here are few small additions:
For #2. – Problem record should be opened. In that way, you'll have recording of activities and you'll be able to overview problem resolution
For #3 – If that workaround is relevant for end-users then this approach should be used. If not, it will be overhead for them.

Here are few articles that may provide further information:
How to ma ke your ITIL/ISO 20000 Problem Management more effective with a Problem Record https://advisera.com/20000academy/blog/2017/02/14/how-to-make-your-itiliso-20000-problem-management-more-effective-with-a-problem-record/
How to resolve the problem ticket/record according to ITIL/ISO 20000 https://advisera.com/20000academy/blog/2016/04/05/how-to-resolve-the-problem-ticketrecord-according-to-itiliso-20000/