i think that the celtic band you have would come back to life with a rework using just b/g and possibly a couple of white hilights thrown in, the tribal work you posted to go with it would look out of place as it is not celtic.

i would advise sticking with something like celtic cross or celtic dragon and stonework etc to accompany it, go to devientart.com and search for celtic tattoo, you will get plenty of ideas

thats just my 2 pennies worth 😉