The short answer is yes:
302.4c To determine a creatures power and toughness, start with the numbers printed in its lowerright corner, then apply any applicable continuous effects. (See rule 613, Interaction ofContinuous Effects.)
March 13, 2015 10:45 p.m.
Actually it would be a no, that card enters th battlefield as a 1/1 and then the +1/+1 bonuses are applied
March 14, 2015 1:30 a.m.
The first answer is the correct one - continuous abilities always apply to permanents that would enter the battlefield. the mighty Spirit of the Labyrinth will enter the battlefield as a 4/2 under the effects of Crusade. Same things apply to Wild Nacatl and Experiment One in this interaction.
NOte that this is not a characteristic definining ability, so it only works while this card is a permanent (i.e. on the battlefield).