Playing bloodthirsty can be quite a challenge in the early game, but there are a few goodies in the happiness file for the endgame
Treaty bonus is just one time, once the treaty is made. Troops are -2 pr. troop, and you will need a lot of them to offset the colonization penalty. Go for troops at once and use a turn or 2 to build some on each planet. Also, a bit later in the game you can try to time your colonization to utilize the maximum anger change of 200 pr turn.