Faber has some askew stuff now and then. Not major, but annoying enough to notice by their frequency. I think it tends to happen with converts from Protestantism.
These 20 devotions should never be ALL implemented at once, and some of them should not even be practiced. This book was not imprimatured by a bishop. Best to ignore it.
No Saint practiced all of these, only very few and not constantly. It's way overdone.
I really don't think he is positing that ALL of them should be implemented together at once (where did you get that from

).
But, you seem concerned about some of them, when you stated,"...some of them should NOT even be practiced."
Which ones?If you think there is some danger then you owe it to everyone to speak up as to WHY you think it is dangerous.
You must be SPECIFIC.
You cannot just waffle and say, "It doesn't have an imprimatur."
Imprimatur from whom?
Not everyone here agrees who could even issue one.
Not everyone is living time-locked in 1961.
Did this work ever end up on the index?
Give us something to work with, otherwise I really don't see what point you are driving at.