Japanese Pocket Questions

Warning I'm still fairly new to the game coming over from Aoe3. This game got me started on the aoe series way back in the day. Anyways I decided to just play the Japanese while I learn the different Strats etc. I only play team games.

My questions;

1. As a pocket player using a infantry civ can I switch my civ most efficient combo in Imperial? I still go for knights in castle but can I make the switch?

2. Whats the go to late game unit combo as japan if I was pocket and opened with knights?

3. Is Heavy Cav archer (My Fav unit) viable as Japanese pocket in Imp after initially going knights in Castle age or should I stick with Cavalier?

4. What's a better Combo CA/Halb/Samurai or Arbalest/Halb/Sam?