I'm building SOHA II as well.
At this moment only 2 parts cannot be found in mouser and Digi-key
Metalized Polyester/Polypropylene Film Capacitor 1μ 63V
C1E, C2L, C2R, C6L, C6R
C4E,C5E Metalized Polyester/Polypropylene Film Capacitor 10n 63V
just wondering if
are good alternate?
Getting the right capacitor is not hard.
Capacitor type - match the type, you can use a different type than specified but you need to know what you are doing.
Capacitance - match the value, you can tweak the value a little sometimes but you need to know what you are doing.
Voltage rating - match the value, higher is fine.
Form factor - Try to match the lead type (radial or axial), lead spacing, lead diameter (smaller is fine) and package size (smaller is fine). If they don't match you would have to mount them the "creative" way which may sometimes cause instability.