What is the theoretical/practical max damage/health of a Lightspawn

From a realistic basis, you can usually get at least a Divine Spirit/Power Word Shield combo which would give you a 14/14 pretty often (make sure you shield first). Although most people won't just leave a Lightspawn as is. It will usually get silenced or removed (hexed, polymorphed, straight up killed), but if they leave it alone, you can get in pretty good shape.

For a theoretical, Jonathan is close but he's missing a card, the Dark Cultist.

Base 5 health + 6 from Temple Enforcers, 2 from Defenders of Argus, 2 from Sun Cleric, and 4 from Power Word Shield gives you a base of 19 to start with.

If you were able to suicide a Dark Cultist (on death +3 health to a friendly minion) and buff the Lightspawn you can get another 6 health. 25 health at this point. This would give you a theoretical maximum of 100.

If you had a Baron Rivendare on the board and the "moons perfectly align" (all 4 deathrattles went to the Lightspawn), you could get another 12 health onto the Lightspawn. Which would give you a 31 * 4 = 124.

This is only limiting priest cards. If you thoughtstole 2 Avenge cards from a Paladin and had them trigger as well, that would give your Lightspawn another 4 health (not sure how the +3 attack factors in because of the Lightspawn's ability).

If you also thoughtstole a sword of justice we can add another point of health.

Final theoretical Priest max base Lightspawn 5 + 6 (Temple Enforcers) + 2 (Sun Cleric) + 2 (Defender of Argus) + 4 (Power word shield) + 12 (Dark Cultist/Baron) = 33 base health. 33 * 4 = 132

4 denoted for double divine spirit

These are assuming perfect thoughtstolen cards.

Max vs Paladin: +1 (Sword of Justice) +4 Avenge = 38 * 4 = 152

Max vs Warrior: -1 to Activate Rampage +6 Rampage = 38 * 4 = 152

Max vs Warlock: +8 (2x Power Overwhelming) = 41 * 4 = 164 (Dies at end of turn)

Max vs Druid: +4 (2x Mark of Wild) +8 (2x Mark of Nature) = 45 * 4 = 180

That would take several turns to setup and perfect alignment of randomness.

I'd like to add a similar alternative. Using Mogu'shan Warden (1/7 Taunt), Power Word: Shield (+2 Health) and Divine spirit (double Health) twice and then Inner Fire (makes a Minion's Attack equal to its Health), you get a 44/44 Minion. The good part about this, is that if the Minion is dealt a lot of damage, it doesn't lose any damage.

There is also Temple Enforcer (6 mana, gives target friendly Minion + 3 Health). This easily works in conjunction as well.