ひとつには…ためである => Partly because of ... N3
Cause, reason
…ときたひには => when it comes to N2
Story topic
ひとつ => A little N3
Repetition, habit
~ひいては => by extension N1
Add
ぜひ => by all means; certainly; definitely ~ N5
ひじょうに => very; extremely; exceedingly N3
Description
~にたえる (耐える)    => bear doing ~ N1
…ひとつも…ない => cannot possibly be ~ N2
Evaluate
もうひとつ…ない => (not) anymore N2
Description
... ひとつ…ない => nothing/not at all… N2
Emphasize the negative meaning
~たると ... たるとをとわず => regardless of; irrespective of; no matter~ N1
Simultaneously
ひとつまちがえば => Just (negligence) N3
Ability