How are Goodberries affected by the cleric class features from the Life domain, if at all? I read somewhere that the Life domain's healing bonuses apply to each berry created by the spell — do they? Are there any official answers to this question?
Yes, a Life Domain cleric's Goodberrys are great.
The Disciple of Life feature would make each berry restore 4 hit points, instead of 1, assuming you cast goodberry with a 1st-level slot. (Sage Advice Compendium for fifth edition.)
For any who aren't aware, "Sage Advice" is the long-standing name given to TSR's, then WotC's, official clarifications to rules. Each month questions worth clarifying are answered by Jeremy Crawford, "rules manager" for 5e, and are concatenated into a Sage Advice compendium.
There is a commonly-referenced website called "Sage Advice" which should not be confused with the articles--this site compiles tweets about D&D rules from various sources, and is not authoritative. But it is informative, as some of those tweets come from the designers of D&D5e, including Jeremy Crawford.
Disciple of Life activates when a spell of first level or higher is "used" to restore hit points:
Whenever you use a spell of 1st level or higher to restore hit points to a creature, the creature regains additional hit points equal to 2 + the spell’s level.
Goodberry is level 1, and it certainly is used to restore hit points:
Eating a berry restores 1 hit point
This also applies to other spells which are used to restore hit points directly, as well as indirectly; such as Healing Spirit, Aura of Life, or even Wish.