re: "would it be safe to say that a quick screen would be a simple task that one of the main tasks of the job . if they fail that task then they defentally wouldnt be fit for an interview even"
Yes, this is exactly what you should do.
Interviews are a waste of time for most jobs.
It is better to do a quick "screen" (to use your word), or a paid test, to use Christy's term.
This simply means that you hire contractors for a short time, or to do on small task.
I recommend that you hire them to do actual work that you need done. That way, if they know what they're doing, you get actual work done that you can use. And having them do real work for your project is a better way to gauge how they will do than giving them fake tasks to do.
How long you will hire them for depends on the type of work that you need done. If you are hiring writers, you could hire them for only ten to twenty minutes. That will be enough to gauge how they write, whether they actually know how to write well enough to work on your project, whether they do their own writing or just copy stuff from the Internet, etc.
If you are hiring a web developer, you might hire them for at least an hour or two hours of work.
If you want to hire by task, you might ask writers to write a short article of only 3 to 5 paragraphs in length. You might hire a web developer to create a single page. You might hire a programmer to create a single function.
You and your project manager will examine all the work turned in as part of these test jobs and determine who you should continue working with and you should stop working with.
Doing this is less time-consuming and less expensive than hiring even one wrong contractor to work on a large project. Hiring contractors for short periods of time or to do small paid test jobs is the ideal way to see what kind of work they will do when you actually hire them to work on a project. Because they've actually been hired. They're actually working on your project rather than just telling you stuff of showing you portfolio items, which may or may not be work they actually did themselves.