What could be causing this rattling noise?

It does sound like there's been a decent examination of the suspension components, to the point that many items have been changed. However, a noise that can be heard is something that should be traced down by a hands on technician. If it's actively happening, it can be found. Even something like an engine mount is possible to be a concern. Noise could also be traveling - what if it's not coming exactly from the front passenger side after all? Too hard to know. Here's a link to find some shops near you to help: www.repairpal.com/repair-shops

Did you ever find out what was causing the noise? I have a 2015 accord that is doing the exact same thing Sounds like the wheel may rattle off sometimes