Toward Ecosophy

Yes, you could do that. You'd want to keep doing the CGD version of the Pentagram ritual and the Exercise of the Central Ray as your daily ritual practice, of course, but that's workable. The one potential source of confusion would come in if you've done anything with the tarot material given in The Coelbren Alphabet, because the FHR tarot correspondences are different -- but so long as you're okay juggling different correspondences, you should be fine.