We use Adobe Connect and have been VERY happy with it. In fact, we have expanded its use throughout the enterprise.
For #1: In our Eloqua instance, The URL is brought into the ICS through the ESM. The ICS field is "Field containing Location" and the selection is "Template Event: Adobe Connect URL."
For #2: While we are not B2C, we have not had any issues with Mobile registrations.
Our Adobe Connect can easily handle 500 - 1000 attendees & works with all platforms
