It you are providing more that 4GB of memory, you definitely should be on 64-bit Windows 10 regardless. If you are providing less than 4GB of memory, however, 32-bit Windows 10 may perform slightly better -- but 64-bit Windows 10 is certainly not going to take you into poor-performance territory.
On machines this old, Windows 10 should be able to resolve almost all devices included on your mobo. Updates for drivers - including that for Intel HD Graphics 4000 - should come automatically via Windows Update, but you may want to manually download and install the latest Intel HD Graphics 4000 driver yourself after installing Windows. It is available here: https://downloadcenter.intel.com/download/29473/Intel-Graphics-Driver-for-Windows-15-33-?wapkw=Intel%20HD%20Graphics%204000. Download the 64-bit package in .EXE form and simply run it.
It is unclear to me why you are bringing up the issue of WDDM 1.0 at all. Is something preventing the upgrade from running? As far as I am concerned, you should be installing from scratch regardless.
...S
