Number 3 is a good enough reason to leave it out of your resume. You say that you have gotten good references on the other jobs following it, so expand more on your past 5 years.
See resume is meant for selling purpose of yourself, Don’t mention your week points in your resume. I am not telling to put false information, I just want to say not to give unnecessary information which may be reason of rejection for you, in such cases you can just give your profile details and assigned responsibilities. You know very well that interview is process of rejection, more than selection so only highlight your positive part as much as possible.
I agree with focusing on the positive, but would suggest your avoid deliberately excluding information. I have been in recruitment for many years and have know of job seekers who have had contracts revoked following a company finding out jobs have been purposely left off.
If the job is more than 5 years ago, and you are simply going to summarise positions thereafter, then its fine to do that
If you want to include job descriptions prior to the 10 month work you refer to, then try to re-work the job description for this role to focus on the positives and skills learned and/or brought into the role. Hope this makes sense
Good luck and it’s a good question.