I'm a native English speaker, but I lived overseas in Spanish-speaking countries from ages 10 to 16. My accent isn't native, but it's passible. The accent in these songs isn't terrible, but it's quite bad... nowhere near something native. If you're trying to teach your kids Spanish, you might as well teach them to pronounce things correctly! Why TEACH a bad accent deliberately? Usually people have bad accents because it's unavoidable if you pick up a language after age 12 or so, but if you're starting with younger kids, why go for a "gringo" accent if you can avoid it?