I know many might disagree and say it will confuse but with my ds we used the dummy for naps only whilst sleep training at night and then once we knew he could sleep through we would occasionally use it if hebwoje early. Sometimes we would use it and sonetmes we wouldn't and generally tried to use it sparingly. Gradually he needed it leas an less and as he got older he got better at nappy g and eventually we were using it only to extend naps if he woke early or at night if we couldn't settle him any other way.
At 18 months there came a point where he napped well and slept well at night for a few weeks and when one morning he wine at 5am I went to give him the dummy (previously our option) he laughed and pushed my hand away
Basically I think it's possible to have '"limited' use of the dummy without confusing them
