In theory, blindsense, tremorsense, and lifesense work differently. But in DDO they might be coded the same. (not sure.)
(remember, everything I am saying here is old news and may not be current)
Ghost showed me in the Subterrain, that when you exited a portal near the Fiendish spiders, that they did not become aware of you until you moved (since they were not facing you at the time you appeared.)
I also think he told me that Tharask Hounds have blindsense, but only in front of them.
Bats, I am unsure of.
Oozes and spiders have tremor sense that pretty much detects you as soon as you move no matter which way they are facing. Ghoste was pretty sure they actually had a front side to them, but that it was just about impossible to tell which way they were actually facing.
Dread Wraiths in the Orchard seem to have Lifesense, that so far seems to work just like Tremorsense as far as I know.
What I believe he discovered and commented on, was that he could move past some Oozes by using the Leap of Faith type abilities.
When I heard this, I decided to try it out. I took a high level Monk into Redfangs and attempted to sneak past the Spiders.
I could in fact, move behind them undetected. But I discovered that as soon as they faced me they saw me even if I was invisible.
So it seems that in addition to the tremor sense ability they have an added "see all" ability in their viewing arc.
I told Ghoste this and I believe he tested it too. Since he had been trying with Oozes (living spells actually_ he had not noticed that the direction they were facing made a difference. But I believe he later confirmed it.
I need to experiment with Tumbling. Tumbling used to force us out of sneak mode.
I never thought about whether Tumbling made noise or not.
(we can even tumble through monsters now.... might be interesting...
)