True?

Same item doesnt , so no more Philo stacking , but different items do.

Not with themselves.
2X Heart of Gold doesn't stack.
1X HoG + Philo stone does stack.

As long as they're unique items, the Gp5 bonus will stack. But you can only use one of each.

If you by the same gold/5 item twice it doesn't stack, but if you buy one philostone, one heart of gold and one lucky pick you will get 15gold/10 seconds

and tear of the godess and archangel staff stack or not?
ill get +1k or +2k mana, if i have both ?

you can't have boots, philo and 4 Healrts of Gold anymore, but you can have different gold items and they stack

philo+HoG+Kage's dagger is pretty decent on supports and i keep doing philo+HoG on most of my junglers and roamers

manamune does not stack with itself its unique, it works with arch angel though

heart of gold, philo stone and kage's lucky pick...