Presubmission inquiry sent to multiple co-editors in the same journals Those editors are from different institutes with different interests. I am not sure who would be interested. I can only send presubmission inquiries directly to the co-editors' institutional emails.

The journal does not have an editor-in-chief.

Is this a bad practice? Shall I disclose that I am sending the inquiry to multiple editors?
Don't ask multiple editors. Ask the one who's most appropriate. Who is most appropriate depends on your query, but the obvious candidate is the editor-in-chief.

Emailing several different editors is kind of pointless because they're all subordinate to the editor-in-chief anyway and probably will defer to the EiC's decision.