The above posts and accompanying sutta references are very good.
From a personal, practical perspective, we don't need to know whether every
single teacher out there is right for us - we just need to find (at least) one that is... and that one needn't exclude "textual teachers" such as the Buddha himself, as transmitted via the Sutta Pitaka, or the authors of ancient anthologies like the Visuddhimagga and Vimuttimagga, or the authors of more recent and well regarded compendiums on meditation and Dhamma practice.
In the quest towards finding (at least) one guide that works for you, feel free to ask questions here of Dhamma Wheel members and other Buddhist practitioners, asking for any reason why you would not take a particular teacher or reference as a guide. If after being appraised of any caveats you're satisfied with the guide(s) you have selected... then it's just a case of putting in the hard yards. In doing your research, you may as well leverage the thoughts, experiences and perspectives of other dedicated practitioners.