I would say elemental would be a waste of gems if your only looking for certain ones in my opinion. Pulling a 5* is tough as you know.
I haven’t pulled either Leo, Vivica, or Justice in just under a year of playing but out of the 2 I would prefer Leo now. He has been buffed so he is decent now. Justice is decent for the blind all but she doesn’t hit hard. Vivica is a real pain to face if she gets going. She works as a pretty good tank.
Joon I pulled early and is great and helps a lot. My other 5* yellow are 2x Drake at 70. Really only use them in wars and purple titans.
In your situation I would just use what you have and not worry about it as much. Leo and Viv both work well. You can easily build teams around both of them.
They say Guin is the “prize” but I don’t really want her as she is a 1 trick pony. Delilah on the other hand would be nice when she comes back around. Then there is the next HOTM. I hope I have better luck next month, this month was horrible for me in pulls. All I wanted was the big guy in the red suit…