I added a schema entry for pc:

<xsl:stylesheet	version="1.0"
	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
	xmlns:dfs="http://schemas.microsoft.com/office/infopath/2003/dataFormSolution"
	xmlns:d="http://schemas.microsoft.com/office/infopath/2009/WSSList/dataFields"
	xmlns:pc="http://schemas.microsoft.com/office/infopath/2007/PartnerControls"
	xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2016-06-01T13:26:27"
	>
	
	
	
fixed a small typo I had at bottom of XSLT (a misplaced /)
and changed the middle of the transform to look like this:
<my:UserSchedules>
			<pc:DisplayName>
				<xsl:value-of select="d:Account/pc:Person/pc:DisplayName" />
			</pc:DisplayName>
			<pc:AccountId>
				<xsl:value-of select="d:Account/pc:Person/pc:AccountId" />
			</pc:AccountId>
			<pc:AccountType>
				<xsl:value-of select="d:Account/pc:Person/pc:AccountType" />
			</pc:AccountType>			
		</my:UserSchedules>	

This is error message rules now gives now:
An error occurred setting the result of the transform. Schema validation found non-datatype errors. 

So I am guessing(hoping really) that we don't need to add the 3 nodes below the person field and rework that perhaps?  Not sure.