Upgrade Appian from 7.2 to 18.1

o update the Dear all,

I would like to upgrade my original environment from 7.2 to 18.1.

Having considered the complexity and availability of Appian packages necessary for the upgrade as mentioned in :

https://community.appian.com/discussions/f/administration/11398/upgrade-appian-from-7-2-to-17-3

I decided to set up a whole new environment, stop all processes in 7.2, and migrate all DB tables to 18.1. All process will be initiated again in 18.1 with the deployed Applications so no deployment of engines data is required. 

During this upgrade, some special changes and measures would be taken:

1. DB Primary Database will be changed from MSSQL to MySQL --> Could I just set up new DB connections in Admin Console and change the Data Source in the Data Store Element, so I would not need to change anything in the DB nodes in the Process Models?

2. How should I handle the "awaited forms" (i.e. those UI forms with "~" logo next to it in the PM) in the new environment, as these types of forms should no longer be exist in new versions of Appian?

Do you know what should I do with the above changes? or is there any further considerations I should have for the upgrade?

Any response would be appreciated. Thanks in advance! :)