I only did a search on Mouser.
Cin & Cin2 - the most important spec is the voltage spec. For these, you should give plenty of extra headroom, like 200V to 400V rating. You are going to have a harder time finding 3.9uF, so look for either 3.3uF or 4.7uF, or combine one of each to make 4uF, but doubles your cost. Do searches on Mouser and DigiKey for "Film Capacitor" of 200V or higher.
yes, major price shock, because high-voltage capacitors go up in cost as you increase the capacitance values.
Cout - You might want to find a cap with an ESR closer to the value that is recommended, since that part of the schematic can be more sensitive to ESR. I'm not a switching power supply expert, so I can't tell you if this is important or not. Technically you could use 10V cap, but I always prefer at least 2x voltage headroom if I can get them for similar price. Heck, depending on the capacitors, sometimes a slightly higher voltage is cheaper because they are more popular and have more competitors to drive down the price. I would look for 16V and 25V caps for building one of a kind project, but if I was making a bazillion of something then I would consider 10V if there was a price savings. Do searches on Mouser and DigiKey for "Aluminum Polymer Capacitor"" of 10V or higher.
These types of capacitors are great, but expensive. If you had to make a bunch of these power supplies and save money, it would be better to investigate using a combination of higher-capacitance ceramic cap to get the low ESR + very cheap aluminum cap, but you need to investigate more to do it right.