Do 10-25% of those with classical eds who tested negative for vascular eds have vascular issues?

Depends. Would not focus so much on percentages, but instead would present your symptoms to your rheumatologist. Would try to seek out eds centers who understand the condition more than most and have seen a larger volume of eds patients (usually at university hospitals).
No. If a comprehensive evaluation is done the people with vascular risk can be determined. The incidence of vascular complications reflects available testing about 15 years ago. With improved testing techniques unanticipated vascular complications are rare without additional risk factors to include smoking.