They *should* be fine. Q3 seems to be actually the same component (BU406), while the replacement you found for CR1 is an upgrade of the original component, with response time of 150 ns instead of the original 200 ns and similar current/voltage specs. 
If you want to go with a component which is as close as possible to the original one, digikey is still selling the GI824 (which is the original CR1), or you could buy this one which is even faster. 
As others have already told you, try replacing Q3, CR1 and the flyback first and go from there: be prepared to what could be a rather long trial & error process, though!