I've had several enquiries about adding tacks to character shoes - including a couple from people who were sold character shoes as flamenco shoes, and didn't discover their mistake until too late.
I have bad news, I'm afraid - you can't add nails to character shoes, or any other normal shoe for that matter.
The soles of most shoes are too thin to take tacks - the points will eventually poke right through and into your foot. If the shoemaker uses smaller tacks to avoid that problem, they're unlikely to stay in the shoe for long! The average sole isn't strong enough to take the stress of all that extra metal, either.
You might get away with adding nails to tap shoes or Irish dancing shoes, both of which have stronger soles to support the weight of metal plates. However, finding a cobbler who understands how to layer flamenco tacks is another challenge altogether!
If you want to make a flamenco sound with your feet, there really is no substitute for proper flamenco shoes.

hi, I have a pair of Gallardo shoes, and the soles are worn out. Any suggestions on where to have them replaced here in the US?
Thanks!
That’s a tough question! It would be easy for any good shoemaker to replace the soles, because there’s nothing unusual about them – but finding someone who can replace the tacks is a challenge.
I assume you’ve already asked your teacher and other students.
I suggest you look for a good shoemaker in your area – not a “quickie” kiosk, but someone who offers complex services like re-covering shoes for weddings. If they value their reputation, they should give you an honest opinion on whether they can do it. The tacks are not hard to get, it’s just how to apply them that’s the problem – and if the shoemaker knows what he’s doing, he should be able to copy what’s already on the shoes. Good luck!