According to the document Installing Exchange on a domain controller, installing Exchange on a domain controller will affect the following points:
• AD split permissions isn’t supported.
• The Exchange Trusted Subsystem USG is added to the domain admin group. And all Exchange Servers in the domain will be granted domain administrator rights.
• Performance of Exchange Server and AD.
• Make sure the Exchange Server is installed on a global catalog server. According to your situation, you could bypass this point.
• System shutdown will take considerably longer.
• Demoting a DC to a member server isn’t supported.
• Running Exchange on a clustered node that is also an Active Directory domain controller isn’t supported.
In addition, as Mikael said, there is nothing would prevent things from working in your image, so you could continue to migrate your Exchange Server 2010 to 2016. To learn more details about the steps of migration, you could refer to the link: https://www.kerneldatarecovery.com/blog/step-by-step-guide-for-migrating-exchange-server-2010-to-2016-part-5/. Hope everything goes well with you!