Keep in mind that the 35 Hz spec is meaningless. For Shure, their spec might be a -1dB point where as JVC might use a -10dB point. The shures could be rated to 25 Hz at -10dB perhaps, but who knows? My point is, unless they tell you the sound pressure level at that frequency and the harmonic content, the frequency itself doesn't tell you anything.
Earphones can do 5 Hz, but they are down by greater than 80dB at that point if not more. Doesn't mean they can't do 5 Hz, so there is no one that can stop a manufacturer from stating that they do 5 Hz. They just don't do 5 Hz as well as they do 100hz or 3khz etc.
I reread your posts, the following is more applicable to your question:
The amount of bass coming from an IEM is very related to how well they are sealed within your ear canal. A slight leak due to an imperfect fit will eliminate the bass. This is why the upper end IEMs make you get your ears fitted by an ear doctor who takes a mold of your ear canal, sends it out to the IEM manufacturer, and you get personalized IEMs that are virtually a perfect fit (Westone and UE do this).
Assuming a very good fit, most if not all of the Shure IEMs get reasonable response down below 20Hz. This evident in their SE110-SE410 current IEMs. I may be assuming incorrectly, but I would think the SE410 is comparable to the E4C