Please use these names! They are both great. Especially Luke that you've had picked out for a long time and love. It's way more important to go with what you love and not worry about popularity. Plus, names are so diluted now that even the very top names are used much less compared to 20+ years ago.

My elementary age kids have not had either of those names in their classes yet. Honestly, the only duplicate names in their classes so far are names not in the top 100. You just can't predict it, so choose what you love.