I recently painted the fascia board below the flashing on the back of my house. Then I looked up and realized I should have done something to the flashing. I went back and painted the flashing with Rustoleum Painter's Touch metallic paint in aged copper. It looks fine, mostly it looks brown. Having done that, I agree with your husband. The satin will look fine. Here is a link that might be useful: Painter's Touch

There is not enough information in the post to give a definitive answer to the question. The structure is located in Fremont, California therefore you are under the California Plumbing Code which is primarily based upon the Uniform Plumbing Code. Unlike the International Residential Code, the Uniform Plumbing Code does not require a "Main Vent" but instead it requires the combined aggregate cross sectional area of all vents to be equal to or greater than the cross sectional area of the building main drain. Under the IRC once we have established the Main Vent all additional auxiliary vents may be reduced to 1/2 the diameter of the line they serve providing that no vent is less than 1-1/4" diam. \ Under the UPC & Calif code all vents may be reduced in size providing you still achieve the minimum required cross sectional area of venting however the UPC sets a minimum size of each vent based upon the DFU (drainage fixture unit) load on the line being served by that vent. In order to answer the original question we would need to know the total DFU load for the entire structure, the diameter of the building main drain and the number and size of all vents. On the other hand, I fail to see how installing the additional vent as defined by your plumber would cause any significant price increase for the roofing job. You simply cut a hole in the roof decking, run the vent line up and slip a flashing on the vent line. Understanding that the flashing is $10 or less I fail to see how it could significantly impact the cost of your roof.

Per 2010 IRC Code, Polyurethane spray foam insulation may be used in an UNVENTED roof per below: SECTION R806 ROOF VENTILATION R806.1 Ventilation required. Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Ventilation openings shall have a least dimension of 1/16 inch (1.6 mm) minimum and 1/4 inch (6.4 mm) maximum. Ventilation openings having a dimension greater than 1/4 inch (6.4 mm) shall be provided with corrosion-resistant wire cloth screening, hardware cloth, or similar material with openings having a minimum dimension of 1/16 inch (1.6 mm) minimum and 1/4 inch (6.4 mm) maximum. Openings in roof framing members shall conform to the requirements of Section R802.7. R806.2 Minimum area. The total net free ventilating area shall not be less than 1/150 of the area of the space ventilated except that reduction of the total area to 1/300 is permitted provided that at least 50 percent and not more than 80 percent of the required ventilating area is provided by ventilators located in the upper portion of the space to be ventilated at least 3 feet (914 mm) above the eave or cornice vents with the balance of the required ventilation provided by eave or cornice vents. As an alternative, the net free cross-ventilation area may be reduced to 1/300 when a Class I or II vapor barrier is installed on the warm-in-winter side of the ceiling. R806.3 Vent and insulation clearance. Where eave or cornice vents are installed, insulation shall not block the free flow of air. A minimum of a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent. R806.4 Unvented attic assemblies. Unvented attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) shall be permitted if all the following conditions are met: The unvented attic space is completely contained within the building thermal envelope. No interior vapor retarders (Class I or II) are installed on the ceiling side (attic floor) of the unvented attic assembly. Where wood shingles or shakes are used, a minimum 1/4 inch (6 mm) vented air space separates the shingles or shakes and the roofing underlayment above the structural sheathing. In climate zones 5 and 6 any air-impermeable (eg.- spray foam) insulation shall be a Class III vapor retarder, or shall have a vapor retarder coating or covering in direct contact with the underside of the insulation. Either Items 5.1, 5.2 or 5.3 shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing. 5.1. Air-impermeable (eg. spray foam) insulation only. Insulation shall be applied in direct contact with the underside of the structural roof sheathing. 5.2. Air-permeable (eg. fiberglass or cellulose) insulation only. In addition to the air-permeable insulation installed directly below the structural sheathing, rigid board sheet insulation shall be installed directly above the structural roof sheathing as specified in Table R806.4 for condensation control. 5.3. Air-impermeable and air-permeable insulation. The air-impermeable (eg. spray foam) insulation shall be applied in direct contact with the underside of the structural roof sheathing as specified in Table R806.4 for condensation control. The air-permeable (eg. fiberglass or cellulose) insulation shall be installed directly under the air-impermeable (eg. spray foam) insulation. TABLE 806.4 INSULATION FOR CONDENSATION CONTROL CLIMATE ZONE MINIMUM RIGID BOARD OR AIR-IMPERMEABLE INSULATION R-VALUEa 4 R-15 5 R-20 6 R-25

The ducting is not suspended from the roof jack and especially not that short a length. Your approach for locating is correct, but in addition, cut a small hole and adjust from there, allow the ducting to protrude above the foam and use spray foam as a filler. Use a urethane caulking to attach the roof jack to the foam, then lap the edges of the roof jack with fiberglass tape saturated with the urethane caulking to seal.