Yes, both FO3 and FO:NV run under Windows 10 just fine for me. Although, my installations are different from default.
Fallout 3 Retail is installed under C:\Games\Fallout 3
Steam is installed under C:\Steam
Fallout: New Vegas is installed under C:\Steam\Steamapps\Common\Fallout New Vegas
I did it this way to ensure UAE wouldn't interfere with the games and it is recommended by multiple websites.
As far as work-arounds with Windows 10, I have not found any that would be helpful to your situation.
i7 4790k @ 4Ghz, 4.4 Turbo
Custom Liquid Cooling
Patriot 16 GB (4 x 8 GB) 2133 @ 11-11-11-27
eVGA GTX Titan X @ Stock
Samsung EVO 1 TB SSD - O/S
Samsung EVO 1 TB SSD - Storage
Seasonic X-1250 Power Supply
Thermaltake Core X9 Chassis
Samsung UD590 3840 x 2160
Windows 7 Ultimate x64