I know of one plugin that won't work with this:
NativeVotes 1.1 has an entire infrastructure (
natives,
implementation) in place to manage the TF2
callvote menu. 1.0 did as well, but then Valve changed the VoteSetup usermessage and forced me to rewrite it.
MapChooser Extended 1.11, or more accurately its subplugins Nominations Extended and RockTheVote Extended, hook into the previously mentioned NativeVotes callvote infrastructure, specifically for the NextLevel and ChangeLevel vote types.
None of the above plugins have had a public release yet. NativeVotes 1.1 was close to release, but then I decided to add support for No Vote like the standard vote system and it still needs testing.
On a side note, the ServerMapCycle you mention is likely used by the
listmaps command. I'm pretty sure it's populated with the maps from the file mentioned in the
mapcyclefile cvar.
It's also likely used if you're not using a third-party map voting system, but that's not really relevant here.