Here to agree on the location of the coolant leak. You also know there is a pan plug missing which I'm guessing is why you were under there. The gasket maker on there is interesting, but seems to be working. Should just be a copper crush washer. I would inspect those pan threads to figure out why gasket maker was used. May have been over-torqued.
+1 heater t's. I thought my transmission puked in my driveway at first, red fluid must be atf..... nope, when i opened the hood there was obvious coolant splatter on the drivers side rear area of the bay dripping down.
make sure you get quality parts, i thought i ordered OEM heater t's, they even came in bags with toyota stickers w/ part numbers but they were fakes upon closer inspection. Ended up with 4 season galvanized heater T's