I also speak fluent French, I used to teach FSL and immersion, as well as knowing German and Spanish. More recently I learned Biblical Greek and Hebrew. Growing up, I was probably the last generation of Canadians who were drilled in grammar - both English and French. And Greek is all grammar, along with vocabulary. Which is why I did so well in Greek in Seminary and now that I am taking Intermediate Grammar. I remember how many dropped out of Greek, because they had no background in grammar, which is very sad, I think. My sister is 8 years younger than me, and she had no grammar and no math, and it hindered her in a lot of things - although she did become a lawyer!
So no, grace is not capitalized, unless it is a proper noun that stands alone. And when you make it stand alone, you are separating it from God. Grace is an amazing gift, there is no doubt about it. But a gift is a common noun, and the gift is not the giver - the giver is God and he alone deserves the capitalization for being a proper noun - Father, Son and Holy Spirit.
Which I believe is part of the whole point of this thread.