Vedic Aryans, Confucius, Zoroaster. They would have no choice but to submit.

 The "clash" of religions is an artificial creation by the sectarian peoples. Masses.

I believe that the Vedic Aryans composing the Gathas, Zoroaster and his followers, If a clear message have come to them to follow the straight path and to Worship God. They would listen and obey.

In fact many of their descendants have done so.

Philosophies developed by cultures is not something that should be used against the Message of the prophets of Islam. It is an aid to it. A correction. 

Do not clash the "religions" because of "identities". 

God is all Good

Worship of God, following the prophets, leads to the virtues of all goodness. Inner and outer. 

In supreme godly morals, angelic characteristics that all politicians fake.

A deep consequence of following your nature and obeying God. Since virtue and good characteristics 

are what all humanity strive for in fake speech but is attained by the worshipper of God 

in his foundation, solid, natural and brick like. In killing he cherishes life that only God can take the soul believes all judgement.

rests in actions linked to the hereafter.