Re: Praying in Arabic?
The reason we pray in Arabic worldwide is to strengthen and unify the Muslims as one community.
Example: If you travel often, and your morning prayer might be behind an imam in Africa, while the night prayer behind an imam in Indonesia. You may not understand the language that locals communicate in, but the minute you step in the mosque and rows are formed, you instantly understand what is being said and what is going on because the prayer is same everywhere in the world.
The real message of Quran is constructed within the highest caliber use of Arabic, which makes even the native arabs ponder over the Scripture Miracle that we're blessed with.
But universality, and one grand community is the reason prayer is in Arabic, and thus important to carry on as such. It's another thing that binds us together in today's world of immense divisions.
Allah knows best. I apologize for not addressing your question(s) as you had requested. But I just shared my thoughts on the issue briefly.