I can't find any reference online for the consultant in Qatar. But Spot Engineering does have a LinkedIn profile. That alone doesn't make them legitimate though.
Have you formally met a representative from either of these companies yet? Also have they asked for any money yet? Usually asking for money upfront raises suspicion. In most cases consultants should be getting their fee from the employer.
Visa processing times can vary. Have you spoken with the company that you'll be work for.
Also what is the name of the agency you are using to obtain the visa? Perhaps other users of our forum have experiences to share.
Read more on the Visas for Qatar page.