In looking at the spawn function in oUF it does not appear there is a way to override the functionality.
You could modify the spawn function yourself and add an override to it? Maybe this is something they can add to the new version for BfA as well.
Lua Code:
function oUF:Spawn(unit, overrideName)
argcheck(unit, 2, 'string')
if(not style) then return error('Unable to create frame. No styles have been registered.') end
unit = unit:lower()
local name = overrideName or generateName(unit)
local object = CreateFrame('Button', name, oUF_PetBattleFrameHider, 'SecureUnitButtonTemplate')
Private.UpdateUnits(object, unit)
self:DisableBlizzard(unit)
walkObject(object, unit)
object:SetAttribute('unit', unit)
RegisterUnitWatch(object)
return object
end