If a Muslim or a Hindu does the same good works as a Christian, i.e., feed the poor, clothe the naked, love his neighbor as himself, are those works accounted unto them as righteousness? Will THOSE good works account for anything towards THEIR salvation?
Yes, they would, in the following sense. Christ judges the unbaptized based on the extent to which they were ignorant of His teaching. All that is asked of an unbaptized is that he follow the law written in his heart, as St. Paul describes it, that is the Natural Law. For example, that Hindu does not need the gospel to know that stealing and murdering is wrong and many Hindus refrain from theft and murder and live exemplary lives according to the natural law. This conditionis called invincible ignorance. The Hindu has not rejected Christ by being Hindu, -- he never knew Him. The question becomes, does Christ know the Hindu? If yes, then sovereign Christ can save him by converting him to His heart instantly, -- as He converted the Good Thief. That would be extraordinary salvation, based not on the sacraments of the Visible Church but on Christ's sovereign mercy, which is not bound but His own sacraments.
However, we should not presume Christ's Mercy on behalf of that Hindu any more than we should presume His mercy on our own behalf. If I had a Hindu friend I would work to convert him to Christ in his lifetime, even if I see enough merit in him to have hope of his extraordinary salvation. That is because the promise of salvation is only given to the baptized who die in the state of grace. While God want all to be saved, the best assurance of that comes through faith in Christ and a lifetime to prove that faith through works.
This is how I understand the Catholic teaching.
My sense of it is that if it is done out of love, and not trying to obligate the Creator to owe them salvation, then it is not a "work". As I have mentioned, Paul's definition of "work" is when we do anything that tries to obligate God to reward us. He rewards us because He is righteous, not because He owes us. Thus, when a Muslim does something out of love with no alterior motive, we presume that that it is the Spirit of the Lord who abides in that man (as no one can do anything good alone).
That is how I see the Church's teachings and the Scriptures.
Regards