Telion is a UC not an IC. He has Stealth. Stealth applies to units, not models. The USRs very definitely distinguish between 'unit' and 'model'. The terms are never used interchangeably (and they are defined up front in the rulebook). Ergo, unless there is another rule somewhere saying Stealth sometimes applies to models, then Stealth only ever applies to units.
Further, if Telion is bought and you did buy cloaks, you must buy a cloak for Telion and he would have Stealth twice. That would be meaningless, and yet there is no provision in RAW to not buy cloaks for all members of the unit. The reason for that is that Stealth applies to units, not models.
Telion is an upgrade for the unit and his Stealth, per the words actually written in the rulebook, gives the unit a cover save benefit.
The correct question to ask of nay-sayers is 'Can you point to the words in the rulebook that say that Stealth in the case of Telion applies to a model, rather than the unit per the USR?'