So I kept trying to add the managed property to the item_personhoverpanel_copy.html. And it kept failing or showing that the ctx.currentitem doesnot have that value.
But when I added the managed property to the item_person_copy.html, it has started coming up with value.
I guess to add a managed property to hoverpanel display template it needs to be added to the item display template first.
However I have the Work phone property now displaying on the display template.
Also I was creating the result type copy at site level. Once I created a copy of the result type at site collection level, the property sync message started displaying when editing a display template.
if(has_phone == true) {
var encodedVal = Srch.U.getTrimmedProcessedHHXMLString(Srch.U.getMultipleHHXMLNodeValues(hhProps, "Workphone", 5, delimiter), 145);
if (Srch.U.e(encodedVal)) { encodedVal = $htmlEncode(Srch.U.getTrimmedString(Srch.U.getUnEncodedMultiValuedResults(ctx.CurrentItem.Workphone, 5, delimiter), 145)) }
if (!Srch.U.e(encodedVal)) {
infoAvailable = true;
if(isExpResult == false) {
_#-->
<li id="Workphone">
<div class="ms-srch-hover-subTitle"><h3 class="ms-soften">_#= $htmlEncode(Srch.Res.hp_PeopleItem_Workphone) =#_</h3></div>
<div class="ms-srch-hover-text" id="_#= $htmlEncode(id + HP.ids.peopleWorkphone) =#_">Workphone :
_#= encodedVal =#_
</div>
</li>
<!--#_
}
_#-->
<!--#_
}
_#-->
<!--#_
}
'Workphone':'Workphone'