Most of your requirements are not things that Visual FoxPro helps you with. Things like Process Word Documents to determine alteration made from master copies are very likely done by way of a COM bridge to Microsoft Office, and it's Word itself which handles the change rather than the vfp runtime.
Assuming that tight integration with Microsoft Office is something you're not considering to change, your best options are the two paths Microsoft offers:
Option 1. Microsoft Access
If you're installing your final tool on desktop that already have a license for Microsoft Office, don't have a team of OOP-savvy developers, and want a WYSIWYG data-management system that couples with office documents, Access is exactly what you want. If you want real security you may need to jump through a few hoops and possibly pick up a SQL Server license, but it's a product niche that overlaps very well with FoxPro and isn't going anywhere anytime soon.
Be aware if you go this path that Microsoft is transitioning Office to have a Software-as-a-Service bias, which may be either detrimental or advantageous depending on the actual needs of your customers and your company's various requirements and policies.
Option 2. Visual Studio
If you're a team of actual software developers with MSDN subscriptions or Visual Studio licenses, using .NET lets you hit all of your requirements plus more, although a more significant amount of training will be required. Visual Studio Tools for Office also lets you inspect and manipulate office documents without launching the final executables, which may grant you a significant speed advantage.
Note that the above are not by any way the only options, nor are they even exclusive. For raw data handling, you'll likely want to migrate to either SQL Server or a F/OSS equivalent such as MaraDB or SQLite, all of which are more than a match for what FoxPro brought to the table for most practical applications.
(There are some instances where FoxPro may be faster than latter-generation relational databases, but there are also several where the relational DB's are significantly faster than FoxPro.)