Individual words broken up by • for emphasis that each word should be spoken separately. •• indicates an intake of breath may be appropriate after saying this, as a way to force yourself to say it correctly.
I found the mistress's attitude ridiculous
I • found • the • mistresses •• attitude • ridiculous.
I presume that there are more than one mistress in reference here, which is also an oddity. I would consider this at best an exercise, and not a regular occurrence. More of a literary device for reading, than for pronunciation.
These are the eggs' shells.
These • are • the • eggs •• shells.
It's important to remember which is which, the shells need to be differentiated from the eggs, so put that extra (yet brief) pause in there.
Which coat is Amos'?
Which • coat • is • Amos? [pronounce the same as if it didn't have the apostrophe]
But note that this is not common usage, so I don't foresee this really coming up often. Mostly only as an exercise.
If it would be beneficial for me to put an IPA pronunciation under each word, say so and I shall do so.