Yes it is. However, I think the Radiance's Animosity is bugged, but still efective against the AI.

it does not work anymore post 1.1....

Never tried that combo before as vasari players end up just bypassin their shields an goin for the kill

The trinity is generally referring to the progenitor, halcyon, and rapture.  These ships are important to the advent battleball.  The progenitor regens the iconus guardians you have.  The halcyon is anti strikecraft and has DPS increasing passive ability.  The rapture can increase the damage of strikecraft and capture enemy ships at level 6.  It is also way to fight off a marza barrage if used right.  The radiance used to be there instead of rapture for the cleansing brilliance/malice combo.  A radiance is still nice but its not quite so important unless you have a marza that you want to disable barrage instead of taking the damage to return it with the rapture ability.

[_]-Greyfox

Vertigo is by far the better ability.

the holy trinity idea didn't survive the 1.11 nerfs to Malice. it doesn't work anymore. 

the battle-ball strat still requires mulitple cap ships though, but there's no longer a specific interaction you're trying to exploit, just general synergy. 

mothership shield regens the guardians (and turns on Malice if you've got enough antimatter). 

radiance AM burns enemy cap ships and generally just protects your own caps from enemy caps by blowing them up with Cleansing Brilliance. 

halcyon screens your battleball from strikers with TK Push and also provides passive damage boost.

rapture is a very important defense against large fleets of LRMS or Lights or Heavies. Vertigo really screws up the damage on any direct firing ships. passive squadron damage boost is just gravy (but still very good). 

every advent fleet will eventually want at least 1 of each of those 4 cap ships. the order you build them in might vary a lot depending on game circumstances though.