Where’s Lucia at

If you are on PC you could try console commands. Load a previous save with Aela, open console(`) and then click on her to find out her id. Copy down the her id. Load back you latest game and use following commands:

• prid "Aela's id" (without the the quotes, "")
• moveto player

That should move Aela to your current location. (You can also probably find her id on the wiki)

If you cannot use another companion, try hiring a mercenary and then going back to a different companion. (Though I am not sure how effective this is)

Apart from that you can try waiting for sometime or fast travelling.

Like all of the Companions, she lives at Jorrvaskr. There are sleeping quarters on the lower level. They don't have separate houses.