I hear what you're saying about making sure your books are balancing post-migration. The vacation balances, however, won't show in any account in the chart of accounts. All the calculations are done behind the scenes in the program and show up on the Vacation and Sick Leave report for you to see.
The Advanced Payroll option does give you the option to map your Chart of Accounts and will show you the payroll vacation broken down into liability and expense accounts. Learn more about that here: How to map the chart of accounts before running payroll
The Standard Payroll option is more basic, so if you'd like to get into more detail, I recommend considering Advanced Payroll. Here's a nice side-by-side comparison chart that outlines the different options: Standard and Advanced payroll features
If you'd like help going over your numbers post-migration, our phone support team can help you out. Don't be afraid to give them a call at 1-855-253-1536. Agents are available from Monday to Friday between 9 a.m. and 8 p.m. EST and Saturday from 9 a.m. to 6 p.m. EST. We absolutely appreciate that you've chosen QuickBooks Online to continue managing your business finances and are here to help make sure you get set up and back to business.