Just wanted to see what you say on the following.
My friend plays a strength 2 horseman, the I play a strength 2 pikeman...do I win because I attack and I have trumph?
You win because the pikemen trumphs the horsemen. Wether you are the attacker or defender is completley and utterly irrelevant. Trumph is trumph.
If so, then my strength 2 pikeman still stands, and my friend plays a strength 2 horseman again...then what? does he win even though I have trumph because he is attacking? or do I win due to the trumph, or is it a tie?
Following the same rules of trumping, you would win. Thus it would make more sense for your friend to play his horsemen in a new front, which would be a totally legal move as you do not HAVE to attack an existing front when playing a unit.
Would he need a strength 3 horseman to win in this case?
Either that or strength 2(or more) archers. The archers would in this case be better as the strength 3 horsemen would be damaged and risk being killed by a possible strength 1 spearman played by you.
No worries. Better to ask and possibly seem dim than to not ask and actually be dim.