The Mac Mini Tech Specs page says (as you mentioned) that the video outputs supported include:
- Thunderbolt port with support for up to 2560-by-1600 resolution
- HDMI port with support for up to 1920-by-1200 resolution
- DVI output using HDMI to DVI Adapter (included)
- Support for dual display and video mirroring
The DVI adapter included with the Mac Mini would work fine. There's no need to buy any additional adapters. Just make sure to get a KVM that supports DVI and supports the maximum resolution of your monitor, and you'll be fine.
The Mini DisplayPort to DVI adaptor listed in the optional add-ons would only be necessary if you wanted to connect two DVI monitors. The HDMI to DVI adapter included for free works fine, so unless you're planning to use two displays, you don't need a DisplayPort to DVI adapter.
HDMI and DVI are 100% compatible, so an HDMI to DVI adapter will work better anyways. DisplayPort and DVI are different electronically. Adapters therefore have a higher chance of being slightly finicky.