I am glad that you could find something to give me reason for the name philip
Thanks. I don't particularly like the name, but if you're fond of it, there's ways to get it used - there's no rule or custom that requires Henry VIII to only use a certain list of names.
I think this is an interesting enough scenario that it would be good to explore some more, personally.
Is it likely? No. But it's not the kind of unlikely that becomes implausible, either - twins happen, leprosy happens.
What might need to be asked though - if Philip gets it, why doesn't Mary?
Sheer luck?
I don't think Henry would disown such a son - but the odds of a leper making it to adulthood aren't very good, so Henry would want to have another son if at all possible.