Does anyone know if MS supports running O365 32 bit in parallel with Virtual Office 2007 (in App-V)? Per the below articles, my guess is yes, but would like to check if anyone got any confirmation from MS on this. 

Supported scenarios for deploying Microsoft Office as an App-V package

How to run Office 2013 alongside an earlier version of Office

In particular, we only want to install Excel 2007 (and not the whole Office 2007 suite) in parallel with O365. It seems Excel 2007 can work on bigger spreadsheets than Excel 365 32 bit.

Hi,

As far as I know, we can install more than one version of Microsoft Office side by side on the same computer by using Microsoft Office coexistence.  We can implement Office coexistence with combinations of all major versions of Office and with installation methods, as applicable, by using the Windows Installer-based (MSi) version of Office, Click-to-Run, and App-V 5.0 SP2.

But, there are some limitations of Office coexistence scenarios, please read this article:

https://technet.microsoft.com/en-us/library/dn770198.aspx?f=255&MSPPError=-2147217396

In additional, I do not think Excel 2007 can handle larger workbook than Excel 365 32 bit. The limitation of workbook size is based on the available memory and system resources

Excel 2007 specifications and limits: https://support.office.com/en-nz/article/Excel-specifications-and-limits-16c69c74-3d6a-4aaf-ba35-e6eb276e8eaa

Excel 2013 specifications and limits: https://support.office.com/en-za/article/Excel-specifications-and-limits-ca36e2dc-1f09-4620-b726-67c00b05040f

Thus, I do not recommend you install Excel 2007 with Office 365.

Regards,

George Zhao
TechNet Community Support