Actually, the swashbuckler's fourth level Bonus Feat class feature states that they count as fighters for qualifying for combat feats, and the fact that it has to say so indicates that no, the ACG playtest classes do not automatically count their "alternate classes".
As to the "most (but not all) state that they count as their component classes", a quick search of the ACG shows that actually, only a minority state anything class to that, and most of them are severely limited as to what they count as their alternate classes for.
Of the classes I've found with such language:
Brawler wrote:
At 1st level, a brawler counts her total brawler level as fighter levels and monk levels for the purpose of qualifying for feats. She counts as a fighter and monk for feats and magic items that have different effects based on whether the character has levels in those classes (such as Stunning Fist and a monk’s robe).
Hunter wrote:
At 1st level, a hunter counts her total hunter level as druid levels and ranger levels for the purpose of qualifying for feats, traits, and options that modify or improve an animal companion.
Bloodrager wrote:
Bloodrage counts as the barbarian’s rage class ability for the purpose of qualifying for feat prerequisites, feat abilities, magic item abilities, and spell effects.
For the purposes of qualifying for feat prerequisites, magic item abilities, and spell effects, greater bloodrage counts as the barbarian’s greater rage ability.
Swashbuckler wrote:
Swashbuckler levels are considered fighter levels for the purpose of meeting combat feat prerequisites.
Only four out of ten classes have such language, so a majority of the hybrid classes do NOT, in fact, count as their "alternate classes" in any way, and none of the classes that DO have such clauses say anything about traits, so it would appear the answer is no.
