You must face errors. You have to understand and fix the errors yourself.
Here u will get answers to all your questions.
1)Can we flash ROM with stock recovery ?
-Yes. There are two solutions. First, we can root our device and then flash ROM with stock recovery using ROM Manager by "Koush".
If u do not want to roo...
Only one question to the former devs of this device. Why is this ROM unstable ? Is there problem with the device tree ? Or with the initial android source code ?
I will start building Lineage OS 15 for S7582 soon.