The only issue I could see with an Online business is that it can be run in theory from anywhere so there is a chance an ECO might think there is no reason to return if the work could wholesale move to the UK. So would need to stress that the business needed to be run from Phill.. Also if she comes over for lets say six months how will the business operate while she is on Holiday?
Sorry for picking holes in the Idea.
I hope you manage to obtain a Visa asap
