base by : ???
I think maybe trying to draw ponies from scratch is your best bet. The style of the mane and tail don't really fit the style of the rest of the base, making it very obvious that it's different. Also, if you are going to use a base, then crediting the correct person is mandatory, or else it's something similar to plagiarism, if not plagiarism itself, which is illegal. Using bases in the first place is very similar to plagiarism if direct consent hasn't been given to use it to draw on directly.