You don't need to explain that you've traveled between jobs, or that you freelanced instead of full-time in a given time period. It's normal, it's your work. If you take too much precious real-estate in the LOE to explain things that they don't really care about, they might actually miss out on something that deserved explanation. Remember, case agents have a target of 100 cases to review each day. Quite a heavy workload.
A 100 cases every day?!! Now, I did not know that! Just out of curiosity, where is that information available?
For work, as long as you satisfy the requirements, you don't need to worry. Freelancing or traveling isn't the kind of red flags they'd be looking for. Unless of course you traveled to some regions known for troubles and unrest, which on the contrary, will raise security flags if you don't have proper explanation. With that I agree. But any other case, don't bother.
No, I think I am okay here.
For professional references, yes that's a good example of additional documents to include. But instead of including it in LOE, include it along with work documents.
To clarify, I meant contacts of professional referees. For example, a manager I directly reported to is no longer in that company. So I thought of including his contact details should someone want to reach out for more details about what I did, because the HR who issued the reference letter in my company cannot answer any technical questions about my job when it comes to establishing validity of NOC.
Yes, you could attach a brief PDF as a first page of each section if you think a brief explanation is needed for something in that section. But in general, keep your "General" LOE as light as possible. They might miss out on important information.
This is what I did initially, but was advised on this forum to keep it simple and just upload only the documents. Any further explanation to be moved to LoE. So, now that the LoE is becoming fat, I need to re-think this.