Recommended approach for transactional SMS consent & MobileConnect keyword setup (UK, Alpha Sender ID)

Hi Everyone,  

We're planning to migrate from a 3rd-party SMS Activity to SFMC MobileConnect for sending one-way transactional SMS using an Alpha Sender ID to UK customers

Note: Our SFMC Business Unit is dedicated to transactional messaging only and is not used for marketing communications

Current architecture

• Customer consent is maintained in Salesforce Service Cloud using Contact Point Consent.
• When an order is cancelled, Order Management System will trigger an event to AIS and AIS sends an event payload to the Journey API Entry Event in SFMC.
• The journey then sends the transactional SMS using 3rd Party SMS activity.

Based on my understanding & questions: 

Based on my understanding, marketing SMS requires consent, while transactional SMS does not. Since our consent is managed in Service Cloud, I'd like to validate the recommended Salesforce approach.

1. Should Journey Builder check Contact Point Consent before sending a transactional SMS?
2.  As per my understanding, transactional SMS doesn't require marketing consent. In that case, should an order cancellation SMS still be sent when the customer's SMS Contact Point Consent is Opted Out, or is it a Salesforce best practice to suppress the message based on consent? 
3. For a one-way setup using an Alpha Sender ID when sending to UK customers, do we need to configure a MobileConnect keyword, or can Journey Builder send the SMS without any keyword configuration?

Has anyone implemented a similar architecture or can share Salesforce best practices? 

Thanks!