1)'to' all my friends or 'for' all my friends . which one is correct?-- Both are fine in various contexts.
2) welcome 'to' India and why not welcome 'in' India?-- 'come' is a verb of movement.
3) get out 'of' the class and why not get out 'from'' the class?-- 'Out of' is an accepted phrasal preposition (or adverb-preposition pair); 'out from' is in use but i