It is good to have the educational certificates attested, a copy submitted along with the application. upon checking with someone, I got the reply is based on your position and salary and the letter from the sponsor, you may be required to submit if it is asked for.
Now any other condition deemed necessary is vague and can be used by the officer to call for any documents he feels relevant to your application.
The ideal situation is that you have all the documents, listed by MOI and others submitted in the first instance to avoid a rejection.

PS. I am not an expert nor a PRO, just a person moved from Dubai to Doha, going through all these hassles to have my family with me. I never thought bringing the family was so tough. The six month bank statement rule was a big hurdle, I had to send my family back to home country so that my kids won’t miss school I need to bring them in by end of next this month before the next term starts or else I have to wait till Next School year. Schools here give admission only if the Residence Permit is processed or else I have pursued the option of Family Visit.