Yes in principle, but seasonality sharpens two tests. The capital must be irrevocably committed and at risk, which seller financing secured on the resort itself is not, and the enterprise must be more than marginal, which a business run entirely by the owning couple for five months a year usually is not.
Seasonal trading is allowed; a seasonal living is the problem
Nothing in the classification requires year-round operation, and plenty of qualifying enterprises trade in a season. What the classification does require is that the business not exist merely to support the investor and family. For the Kavanaghs the practical difference lies in the staffing and revenue plan.
A resort that opens in May with a housekeeping team, a maintenance hand, dock staff and a café crew, generating revenue that supports those wages and more, looks like an operating enterprise. The same twenty-two units cleaned by the two owners with occasional weekend help looks like self-employment with a lake view. The capacity may be demonstrated prospectively where it is not yet present, but a projection is expected to be realistic and to arrive within roughly five years, supported by the seller's actual historical figures rather than by an optimistic model built for the application.