1) No, this is not a vacation home. Nobody, neither you nor tenants used the property as a residence during the construction period. It was personal property, converted to rental property and then vacant property.
2) Yes, an expense is only a rental expense for the time it was actually rented.
3) You said, ", not placed “in-service” until the property was made available for sale in March of 2022". This property was never placed in service. It was never made available for a tenant's use. You can add the appliances to the basis of the building.
Placed in service:
The term placed in service means the time that property is first placed by the taxpayer in a condition or state of readiness and availability for a specifically assigned function, whether for use in a trade or business, for the production of income, in a tax-exempt activity, or in a personal activity.
4) If the assets you are referring to were placed in service during the rental period, you can take them as expenses under the De minimus Safe Harbor rule.
