General

You could try it, up to you, but what @beefly said is a nice recommendation. You might be able to get Legendary, maybe not. If you feel like clicking.

During the first -50% discount I forgot to lock on my Bishop, which caused it losing the Legendary tier. So I clicked it back up to Unique and stopped. I waited till the next event that gave us Circulators, which happened to be the Maplehood Watch. I used 2 and it turned Legendary with 50% buff duration, so good on a Bishop.

Use circulators to get to legendary, at the very least you should try saving as much honor exp to roll legendary lines. Otherwise you may end up on Rare, and the lucky ones usually take 500k exp with 50% off to get the desired legendary line.

I suggest to use circulators to get to legendary and to get the desired line. Use the rest of the honor exp to roll the other 2 lines. If you're feeling lucky you can try getting the desired line with your honor exp once you hit legendary. I personally don't think it's worth trying to rank up with honor, especially if your lines is okay to begin with.

If you have absolutely no money, then do what the first guy said.

Go for it, I went from rare to legendary with 15k honor exp lol which should've been 30k but its 50% off