Tabs: Yup, just paint the Lenco actuators with your anti-fouling paint. Bleach sprayed onto barnacles helps to remove them, I use 50-50 water/bleach in a sprayer, but only spray those areas with barnacles and that you will prep/paint over. Wash area thoroughly with water and then solvent wash (I use acetone).
OB: On the OB bracket, you could try the clear anti-fouling paint 'made for aluminum', but DO NOT put any anti-fouling paint with copper (cuprous oxide) on your OB.
You 'can' only if you do a 3-step method, add a metal etching primer, then a rubber 'tie coat' primer, and then your anti-fouling paint. To not do this would have the paint (copper) interact with the aluminum and with copper being more noble (remember the lesson in dis-similar metals??) the OB would be eaten away (oxidized).
Prop: No sweat, that's the Yam prop that's a low-grade SS that will oxidize. Clean with bronze wool (NEVER use steel wool anywhere on a boat) and paint with hard gloss black enamel spray paint.
Skeg: OK there too, no welding needed. To re-paint, sand with wet/dry paper to remove all signs of any 'white'. This would be aluminum oxidized or salt. Then wash with acetone. Then paint with zinc chromate etching spray paint. Many THIN coats are preferred over one or two thick coats. Then apply sandable primer if need to build up, then apply topcaot of OEM (Yam = expensive) or factory-match (Tempo) paint to match the color.
Simple stuff ...
