1. Pre-event reporting
our needs: share a report with non-Marketo users the day before the event including a number of custom fields such as Phone Number, Industry, Registrant Questions etc.
issue w/ Marketo alternative: as far as I know, a smart list subscription cannot be customised to be shared the day before the event
I don't understand this. If you use a Marketo landing page to register persons, you can ask whatever question on your registration form such as Phone Number, Industry and so on. And you will be able to create Smart List Subscriptions in Marketo that give you all registrants and include all of the fields you had them submit in the registration process.
2. Post-event reporting
our needs: share a report with non-Marketo users a few hours after the event including the custom fields mentioned above, the event status (Attended, No show), and all the attendance information from Gotowebinar
issue w/ Marketo alternative: for this one, the only option I found was creating different reports and combining them using a Vlookup
Unfortunately, I understand this. And I feel you. The Marketo/G2W adapter is old, and nobody ever updated it because neither Adobe nor Citrix/LogMeIn/GoTo felt responsible for it. That's why you don't get all the attendance information from G2W to Marketo. You just get the attended/no-show status, but you don't get Attention Time, Post-Event Surveys, In-Event Polls and whatever else G2W is collecting to Marketo. If you want that information you will need to create a custom integration.