This stream is pretty overwhelming, and there is so much to discuss. I will just outline what I did an hour ago before I share more thoughts.
So before this stream happened, I had a 4.00% pity rate on Celica's Army banner. I did these pulls a few weeks ago, and I was originally going to cut my losses there. Because of the Tempest Trials, I was compelled to get Sonya.
I used 52 F2P Orbs and summoned as many Green Stones as I could. No 5*, no Sonya. My rate was at 4.5%, so I reluctantly spent money. This was the first instance since the last Hero Fest. I had some money in my Paypal, and I bought a $25 card. I bought the 48 Pack, and I got the Sonya (+SPD/-DEF).
Everything else in the Sonya batch was 3*, but at least two of those were Lon'qu and Jagen (both good fodder). This is why I'm actually happy about the 3* and 4* rates getting switched.
Thank God this ended so well after the huge number of Orbs I spent. Celica is very tempting, but I won't even think of getting her with free Orbs. I feel satisfied, so I have no problem saving for a while. I have 25 Orbs left over from the 48 Orb package.
I just got Saber when I wanted Sonya because no green orbs appeared so many times.
Oh well.
If you have Orbs left over, it's not a big deal. Delthea, Celica, Sonya, and Gray will presumably be on a Tempest Trials banner, so you can basically pull anything except Colorless if you want the 40% bonus.
You don't seem to be the F2P type, so there's a lot at stake for the rest of us. What I went through was really risky.