It seems to me the only way i can subscribe to a platform event using a process is if there is a cooresponding record already in salesforce to match again. This is what I see in this documentation under 'Associating a Record'. Is this true? I want to create a record in salesforce based on an action in the extenal system. Do I need to use an apex trigger?

https://help.salesforce.com/articleView?id=process_considerations_design_event.htm&type=0
 

We have a homegrown application that performs authentication\aurthorization via SAML or .net calls. Is it possible to have a site.com website that allows registrations and then authentication by our homegrown applicaiton?

Can we create a sites.com website and use a homegrown authentication\aurthorization tool to secure the website? If so, how is that technically done? I'm having trouble finding this on the salesoforce site

We have a homegrown application that performs authentication\aurthorization via SAML or .net calls. Is it possible to have a site.com website that allows registrations and then authentication by our homegrown applicaiton?