Exchange Hybrid Autodiscover question

Hi Support,

We are now planning to deploy an hybrid scenario with the following configuration:

1. Exchange 2010 SP3 (existing Exchange infrastructure)
2. Exchange 2013 CU21 (hybrid servers with Exchange Online)
3. Exchange 2013 web service will be publish via a reverse proxy to the Internet (e.g. proxy02.contoso.com)
4. AAD Connect (with password synchronization)
5. There is no Autodiscover records created for the existing Exchange 2010 infrastructure (no A record Autodiscover.<email domain> and SRV record _autodiscover._tcp.<email domain>)

We got below questions about the Autodiscover record below as it is a strict requirement for Exchange Online hybrid deployment.

1. Is it a supported scenario to create SRV record (_autodiscover._tcp.<email domain> -> proxy02.contoso.com) to enable the Exchange Online hybrid?
2. If an A record is required (e.g. Autodiscover.<email domain>), can we just use 1 A record for all Autodiscover service of each email domain? As the client got over 20+ authoritative domain in their existing Exchange 2010 enviornment.

Regards,

Leo