My DD and I did it to her awful kitchen in her "new" house. The previous homeowner was a widower, and the place had not been kept up. Sure made a difference, and that was a year ago. We took a few days to do it all, and you can do just a little at a time. We used antique white. The tiles were oatgmeal. Then we found stick-on squares of vinyl floor tile that had the same antique white in them. Covered the floor and the awful cupboard shelves. Painted cupboards a creamy off white and replaced the knobs, and then we used that cream and very pale lemon on the walls. It finally looked clean.

I will answer this one in 2 parts. 1) If you have plaster walls, then your home was most likely built prior to 1978. It depends on the area, I suppose, but the majority of homes built Pre-1978 have dangerous amounts of lead in the paint. Because of this, I highly recommend either getting a lead test before DIY-ing it, or hiring a professional company that's certified to do lead abatement and lead maintenance repainting. If you scrape/sand/etc over lead paint with children in the house, then unfortunately, asthma and allergies will be the least of your worries. Lead has been shown to cause severe birth defects in fetuses of pregnant women, as well as learning deficits, lowered IQ, organ damage, ADHD, and other serious problems in children. It also affects adults, although to a lesser extent. Lead dust/chips, when inhaled or swallowed, stays in the bone marrow for decades and slowly releases into the bloodstream, where it damages organs including the brain, liver, heart, etc. ================================= 2) If by plaster you really meant to say "drywall", then unfortunately, the only way to hide this defect is by applying joint compound, sanding, oil priming and painting. If your son has asthma, a way to counter this is, ironically, doing the same thing a lead abatement company would do: Quarantine the area off with plastic and painters tape (they use duct tape and 6mm plastic for lead, but you dont need all that), turn off the AC/Heat and plastic the vents and return system, and completely box in the area sealed tight. Then, once he is done, have him do the "TSP sandwich"- clean the dust up with TSP mixed with water (8 parts water, 1 part TSP), then have him use a HEPA vacuum to vacuum all of the area, then wet-wipe again with the TSP/water combo. At this point, have the area air scrubbed with a HEPA filter (air scrubber preferably, but a lower strength one will do), then remove the plastic and immediately bag it. Problem solved. ALSO, one more thing:Even if a self-leveling paint could cover this ridge(which it wont, self leveling doesnt work over obvious ridges like that), then you would still need to clean the walls with TSP and water and then apply an oil primer before doing the self-leveling paint, in order to clean and then prime over any remnants of, the wallpaper glue. If you just put the paint over the ridge as it currently is, it would probably start to peel due to the wallpaper glue or glue remnants.

It's always been recommended to prime with an oil primer, even if the topcoat is acrylic. I've done this on rental property over the years and it seems to hold up well. Two topcoats gives the best protection. Have you seen this new paint that's out now where you don't need to prime? I can't remember the name of it but it's about $40 per gallon. My dad used it a couple years ago on vertical siding on his house and it seems to be holding up better than the old system of primer and 2 cover coats. Your paint store should know what you're talking about if you ask them.

I think I have the same siding as you - it looks like Hardi Board. Those nail holes look wrong to me. If those are on every piece of siding then the original installer didn't know what they were doing. Except in special situations, the nails should be covered by the piece of siding above. There should not be nails down low on the siding. Since those holes should not be there, I would think that filling them would be an extra step. FWIW my neighbor has the same siding and the installer caulked the seams between the boards - the vertical seams. It looks horrible because the caulk is a different texture than the siding so it sticks out. Caulking those holes would probably give you the same result - strange shiny dots on your siding. Having said that, giving water a path into the siding is not good either. But if the house is several years old and that has not been a problem, you are probably fine. On the soffit - I would have someone finish that area with an appropriate soffit material that will accept paint well and hide the 2x4s and plywood that are there now. No amount of paint is going to make that look good.