As you have observed, there are many simliarities between students with dyslexia and those for whom English is an additional language (EAL) especially where listening is concerned - in fact, the communication skills of dyslexic students are often described in terms of the early stages of foreign language acquisition - first they process the sound (hear the word) then they process the meaning (translate it from English) - then they think of a response - translate it into English - then respond. The main difference is that your EAL students (unless they also have dyslexia) will improve as their understanding and control of English improves.
Those who employ 'dyslexic' coping strategies may, as you note, not actually have dyselxia - but they may have another specifc learning difficulty - or even a hearing impairment. Many of these are covered in Section 3 Part 2 (i) and 2(ii) of this course.
Even though a student may have no history of dyslexia - and may even be resistant to any suggestion of dyslexia - if coping/avoidance strategies typical of dyselxia are being used, and there is no apparent cognitive difficulty, further investigation should be suggested. It may be presented as an opportunity to 'rule out' certain factors that affect learning - or in a more positive light - re eligibility to Access arrangements for exams. Impaired vision is also a 'hidden' difficulty that many students do not realise they have - or that they try to ignore, being unwilling to wear specs - but vision should also be checked regularly, especially if there is a lot of course reading. When previous coping strategies fail they often develop into reading avoidance - or a belief that the student has less ability than previously thought - or has lost interest.
While it it always possible that a student does lack interest and/or motiviation, this is less common in older teenagers and adults who select their own courses of study.