Hello Michael,
if you use the search pro tool on the top right you can find many threads about switch interoperability.
Here are some suggestions:
all Cisco proprietary protocols like CDP, DTP and VTP are not supported in a multi vendor environment.
As a result of this consistency of the vlan set in use in the campus require explicit configuration on non Cisco switches
Trunk ports have to be configured for trunk mode on (no DTP exchange with peer)
STP modes:
in modern environments 802.1s MST is the most attractive.
Be aware that in some platforms/IOS versions combination cisco switches support a pre standard version called MSTP.
Legacy 802.1D switches can be detected and supported by Cisco switches running PVST+ or Rapid STP.
In these cases cisco switches should be deployed in the core for their multiple STP instances capabilities.
I think TAC should give assistance in multi-vendor scenarios.
Hope to help
Giuseppe