You might try contacting the Honda folks themselves. Call regional headquarters, Customer Service. They will transfer you to their Technical department. Or try email.
I don't know what kind of response you will get. Sometimes these desk technicians can do no better than repeat what's in the owner's manual or other low-powered literature.
If I had to guess, I'd say it should be perfectly OK to move a 6-cyl tire down to a 4-banger model, while it may not be prudent to use the smaller tire upward to the 6-cyl car. So you should be all right. Try a driveway test to ensure thre is no wheel rubbing on lock-to-lock turns.