TGGP, 
 
I think you are right in general about "much of this Protestantization is occurring before they even get on the boat" but not in this particular case. The mandir in Queens in the article is very orthodox in its ritual and attracts the most conservative strand of immigrants. The really assimilated types would probably want to attend say, the Ramakrishna Mission branch on the Upper East Side which -- how's this for protestantization! -- not only has a choir but pews, an organ, and a sermon from a "minister" in its sunday morning "service." Though to be fair, it was founded by American admirers of Vivekananda before the era of Indian mass immigration.

What is fascinating to me is that congregational singing is not in fact an innovation in Hinduism at all atleast since c. 12th century or so. Bhajans are simple, non-ideological, emotionally-oriented call and response type songs, for the most part not in Sanskrit, which are sung by public groups with less caste exclusivity than usually found in society. Often these groups meet in mandirs and the singing has become integrated into the ritual. For North Indians particularly women like the Mrs. Tandon who was interviewed, this is in fact the dominant mode of religious expression. Yet she references Pentacostals as a model instead of her own tradition. Is this only for the white reporters benefit? Is it because she perceives the bhajan tradition as being less prestigious and reinterpreting it in terms of the socially dominant paradigm will upgrade its status? 
 
This article shows the assimilation that is going on is of North Indian forms into a traditionalist South Indian community. In South Indian mandirs, communal singing if it occurs at all is by a specialized caste of singers not the general public and is not really a focus of the worshippers temple experience. Even this article notes that the priests and some of the other worshippers were not paying much attention to the choir. That's not very Protestant is it? 
 
Also interesting is that this is happening in a mandir in Queens which is an area of first settlement. Wouldn't one expect assimilation to be more likely to happen in the suburbs where the upwardly mobile and second-generation live? I have recently visited mandirs in Atlanta, suburban NJ, and Pittsburgh and none of them had choirs as far as I could tell.

Whoo-eee! Did you check out the dowry on that one?