We use three different sets of icons in Hotel California theme: Font Awesome, Stroke 7 and Custom Icons. Please refer to these links for preview of each icon set.
To get Client ID and Access Token please follow the steps from our article: How to set up your Instagram widget?
As with BT Instagram, you need to register an application here to be able to use the widget. Please follow the steps from our article: How to set up your Twitter widget?