tooltip:GetUnit apparently does return what I need. Commented out unit conversion code for now.

diff --git a/Modules/Portrait/Portrait.lua b/Modules/Portrait/Portrait.lua
index b2ca40e..faaff3a 100644
--- a/Modules/Portrait/Portrait.lua
+++ b/Modules/Portrait/Portrait.lua
@@ -98,7 +98,7 @@ function mod:GetOptions()
 end

 function mod:SetUnit()
-	if not self.text or luaTexts.Race(StarTip.unit) == UNKNOWN then return end
+	if not self.text then return end
 	SetPortraitTexture(self.texture, StarTip.unit)
 	if self.db.profile.animated then
 		model:SetUnit(StarTip.unit)
diff --git a/StarTip.lua b/StarTip.lua
index d0d8eec..41e6894 100644
--- a/StarTip.lua
+++ b/StarTip.lua
@@ -650,7 +650,7 @@ end

 function StarTip.OnTooltipSetUnit(...)

-	local unit = GameTooltip:GetUnit()
+	local _, unit = GameTooltip:GetUnit()

 	hideTimer = hideTimer or LibTimer:New("StarTip.Hide", 100, false, hideTooltip, nil, StarTip.db.profile.errorLevel)
 	hideTimer:Start()
@@ -664,7 +664,8 @@ function StarTip.OnTooltipSetUnit(...)
 	lastTime = GetTime()

 	StarTip.fading = false
-	StarTip.unit = "mouseover"
+	StarTip.unit = unit
+	--[[
 	if not UnitExists("mouseover") then
 		if UnitInRaid("player") then
 			for i=1, GetNumRaidMembers() do
@@ -693,7 +694,7 @@ function StarTip.OnTooltipSetUnit(...)
 			end
 		end
 	end
-
+	]]
 	if not UnitExists(StarTip.unit) then GameTooltip:Hide(); return end

 	--[[if StarTip.unit ~= "mouseover" then