This is what i know about this theme...
Bruce is an ATHEIST and he has a anti-church attitude,you can see that in his lyrics and his interes in art,his IDOL is ALEISTER CROWLEY and he is one who inspired Bruce.In faith and music he said that he believes in something because everyone has to believe in something (he probably think about energy and some universum godlike theory) but he also said something like "OFFCOURSE i don't believe in that but..." Because he is a very open minded person,and he has a extreme point of view on almost every subject and that is what makes him a original and briliant artist.
Steve Harris is also atheist but he has almost agnostic attitude,in song like for the greater good of god you can see that he also got some themes and claims which are related to Dickinson point of view.
Dave and Adrian,i think and i cannot be 100% sure that they are in Protestaism.
Nicko Mc Brain is a NEW BORN Christian and he said in some interview that he has a deep conversation with the band about that and that most of them don't share his beliefs but they respect that in every way.
And you got on FINAL FRONTIER Starblind that got a message,deep message,we should not fight for religious beliefes because is pointless,SUN is one religion,you are blinded and you cannot see every single star on the sky because of that,you can't be blinded by one religion because you will be deceived in the end and it will be late.On this tour you also got Blood Brothers that got a prequel speak something like: it donesn;t important in what religion you are it doesn't important what color you are because we are all the same we are MAIDEN fans.GOD in most of Maiden lyrics is just an metaphor.
AND MOST IMPORTANT THING ON THIS TOPIC IS = THAT THIS IS THEIR PRIVATE THING AND I THINK THAT THIS THEME IS UNNECESSARY !!!! They are here to make music for us and we must respect their privacy....