Can Yordel be possessed by Targon aspects?

if it where old lore yordles then yes, new lore yordles not so much.

the old yordles where a physical race living on runeterra with their own city-state.

the new yordles live in an alternate dimension and are more fae-like beings, illaoi describes them as 'spirits' which should go to 'places where men need your help'

they also tend to embody their surrounding area:

Poppy: a knight with a ever-lasting mission, but quite naive (like the demacians)

Kled: bloodthirsty, paranoid and insane. (like the noxians)

Heimerdinger: smart, inventive and by-the-book (like piltovans)

ziggs: smart, inventive and against-the-book (like zaunites, also like explosions as much as jinx)

kennen: ninja, likes balance, lives in ionia (lightning rushes foward, lightning rushes back...)

fizz: an ocean dweller, tricks people, generally disagreeable (like those living in Bilgewater)

tristana, teemo and rumble dont have a places in the new lore yet, they just hang out in bandle city (which is an alternate dimension)

so no, i dont think that yordles can become host to a targonian aspect, considering that they are spiritual beings and already embody their surrounding area.

That's all