Just won vs Green Witch. Had to use a bomb fruit in a pinch, but been really lucky in the run. You can't just expect to use reno + chrome or endurance strats. Just spam AOE and have fun. My units were all lvl 2: pinto, green mage with gun, brown detective that shields, brown shield dude, orange flame knight and green mage that does aoe and holy arrows. The gems were 4 shields (2 normal and 2 cooldown reducing) , 1 fruit, 2 moon wolfs and one tornado. Had pretty much every color and bonus except moon, blue, red and paralysis.
If you guys have questions just let me know. Also, have no idea how to paste screenshots.

I've only played Zeola because I enjoy it more. There are many important strategic decision points throughout a given run. The overarching themes I've utilized are:
- Be as greedy as possible. You want to beat floors with minimal investment into units. Save up carats, sell units, take advantage of the special tiles (double carats in two floors and no gem use on current floor for a strong gem), hold onto your Magic Hammers for as long as possible, take "weaker" accessories that grant more carats, and in the early game use Thieves to gain extra carats. Do whatever you can to earn more carats so long as you are still strong enough to beat the floor.
- Plan for each boss so that you can beat it with minimal investment. This can mean saving a Bomb to clear the boss starting minions, using unit & symbol combinations that hard counter the boss, and ensuring that your gems are well suited for the fight (e.g. make sure you have Medicine for the Shroom boss to avoid negative effects).
- Traveling Jewelers should have a massive impact on your decision making process, but not override the specific situation. In general, you want to exploit the Traveling Jeweler to unlock symbols, build strong unit compositions, and even to 3 star certain key units (e.g. Rock Crab).
- Accessories are nuanced. There are certain accessories that you should prioritize when offered (e.g. Aegis Shield earrings). When you decide to "permanently" lock in an accessory, then you can consider its symbols are statically present. Otherwise, you should sometimes invest in extra symbols to offset the possibility of exchanging an accessory later on in the run (e.g. if you have Carat Ring with Red and it fulfills your third Red requirement, you still need to consider building a fourth Red unit because that Carat Ring probably won't be around forever). Plan for obsolete accessories and the symbols that will potentially be lost with them well in advance.
- You will always need to unlock 3 Green for the health boost.
- The most common strategy for defeating the final boss is to utilize 2 star rare units because they are strong and only cost 90 carats to build. This makes the item Angel Ring incredibly powerful as it can get you to those rare units more frequently.

I'm much more experienced with Amelie, so maybe I can weigh in here.

As you've figured out with green witch, take AoE gems (specifically ones that target the back two units). The sun is great, moon synergizes with the sun, moonlight ring or magic ring will increase your damage further. Don't block at all in the last fight - just let your defensive bonuses take care of it (I recommend a combined 4 points in shield + magician). 40 sunlight with a dragon arrow or a dagger should about 2-hit the lava muchrooms, although it's much safer with 100 sunlight.

The red witch is actually easy if you know how to cheese it. Undeploy all your units that trigger spikes or counter, and run a team like this:
Amelie: lapis/herald/herald/herald/dancer/dancer
Ziola: hermie/hermie/hermie/hermie/hermie
The boss has low base damage and no scaling if you don't trigger counter. Sit there and let it die to spikes or burn or whatever.

The blue boss is pretty hard. Go for the same defensive buffs you'd usually go for, and consider methods of dealing damage which don't involve getting too many buffs. Red/yellow/sun/moon become better here.

Another random tip: if you get an upgrade gem and a hammer gem, you can discard every other gem in your inventory, then use the hammer until it has one use left and upgrade it to refill its uses. You get like +300 gold or something.