[Shovah32]

I know you're talking about elephants in general, but this is LA and elephants, atleast in my opinion, are even better in LA than in other ages.
Firstly, armoured troops are much more common - meaning low defence troops that are just begging to be trampled.

Secondly, astral power is lower. LA R'lyeh is pretty much the only astral heavy nation(Patala has astral too, but they are the ones who will be using elephants), and even though alot of other nations have astral magic it is often not strong enough to make as much of a difference as it could in MA - Pythium and Arco for example both lose some astral magic. Pythium may still have Hydras(and sacred Hydras at that), but pythium in general has less counters than they used to(and Patala, with their strong magic, should have other ways to hurt hydras).

For the original question:
-bless or not: Not. While a bless from whatever pretender you happen to take would be helpful(particularly earth and nature for mages and national summons), it isn't really advisable to actually use a bless strategy with patala.

-elephants or not: Yes, oh god yes. As I have mentioned, I love elephants, particularly in LA. Don't make them exclusively, but make alot of them.

-which mage to recruit the first turns etc: At the start, I would stick with yogis and maybe gurus, you want to be spending most of your gold on elephants, longbows and maybe other castles. Once you can affort to, you probably want to start producing a Nagarishi every turn as they have crazy magic power and also make great site searchers(site searching spells aren't quite as nice in LA due to reduce site frequency).

-which troops: As I've said, longbows and elephants. Produce Bandar Archers when you have a gold shortage and light bandar archers when you don't, and remember that longbows can struggle alot against high protection and shields - so when facing them you can call in the elephants.
You'll want to make quite alot of elephants, but I would use them with other Bandar troops(instead of with your archers) like light warriors(stones+maces, stones get nasty with strength of giants) and heavy warriors(armour+mace) until you are buffing your elephants with your cheap astral mages(and possibly protection via Nagarishis if you have a large force).

Remember, both elephants and longbows both have fairly reliable counters, so prepare for them with your magic when you can. You'll want to clam, summon (particularly your national summons), site search and use battlefield magic with your Nagarishis.
Your nagarishis can buff your troops(the various protection buffs, strength of giants, weapons of sharpness and quickening all come to mind) and lay down serious artillery with spells like bladewind and falling frost, but you're very vunerable to astral magic(magic duel) so keep that in mind.
You'll also want to avoid using S2 Nagarishis in battle, because without them your Gurus will absorb any magic duels thrown your way.

Just some rambling from a crazy person. Hope they help.