Looking at it from the DT natives' POV, the Emberi and especially the Halmes would be excited to learn of an advanced human race that's not trying to kill/conquer them like the Hermionne. As a matter of fact, the Halmes might be more eager than the relatively halcyon Emberi to trade with us, to help them fight off the encroaching Herms. The problem is, what would the Halmes trade in exchange for such help? Some Emberi consider the locusts as holy beings of nature, and despite what we saw Vaelia's son doing with his toy sword, mature Emberi might take issue with capturing them to trade with us. Whether Halmes hold the locusts in the same high regard is not known, maybe they consider them pests too and will be more than happy to round them up for us (which might cause ill will between them and the Emberi if they found out). Of course, if we give Halmes gunpowder weapons to fight off the Herms, not only the Herms but the Drow and the Emberi will all be concerned, as it upsets their own balances of power
Maybe weapons aren't a good idea to trade...perhaps Halmes could just use help with engineering better defenses, or medical technology, or even agricultural knowledge to increase crop yields (won't help them with defense, but sufficient and better quality food might make the Halmes healthier, bigger, stronger, which could tip the scales over time). Again, any help we give one of the ethnic groups will impact the others, so enhancing the Halmes might make them an even bigger target as the Drow join the Herms in trying to take their newly-acquired knowledge and products for themselves
I could imagine the Emberi being very interested in better ship technology. Maybe not full-on motorized boats, but even advanced sail technology could help them greatly. Other things might be stainless steel knives that don't rust and holds a keen edge better, or fabrics for clothing, sails, shelter, load-bearing equipment like packs and belts, footwear, you name it. A simple 'fish finder' would totally be magic for them (but maintaining any form of electronics would be beyond their capabilities, especially power). Other things that they could use right away might be medical (like the Halmes), or meteorological (to predict storms, tidal patterns, etc.), even fresh water supply and sanitation
The Herms won't sit idly by while their opponents get a hand-up. If they don't try to take them by force from the DT natives, they might try to open diplomatic relations with us themselves. They have a sizable empire going, so their information about the world might be more useful to us than the limited areas the Halmes and Emberi control, but knowledge about the Drow might be better found from those goblins who are friendly to them, and not their enemies. Also, from what we've seen of the Herms, they don't have anything we didn't have centuries ago. But they were using fire weapons at Ys, so maybe they have access to crude oil? As we are moving away from fossil fuels, I don't know if we'd want to establish relations with the warlike Herms just for access to their oil (which would be of questionable quality and quantity)
Now the Drow...they think they're at the top of the food chain, I don't see them looking favorably upon goblins that can readily kick their ass militarily. They don't have a problem trading with Halmes and Emberi, because they know them, they are nowhere near as powerful as the weakest Drow clan. If the Drow were willing to trade with a powerful human people, they'd be trading with the Herms already instead of fighting them. They fight the Herms because they know they are superior to them. But Earth humans, who have weapons that measure their effective range in hundreds of meters if not thousands of miles, and can kill dozens if not thousands of people in one shot? Who have artificial 'moons' circling our planet, devices that allow us to communicate around the world, vehicles that can tirelessly (npi, even airplanes have tires
) whisk us along at hundreds of miles per hour to destinations thousands of miles away? I think the reaction would be like if aliens in spaceships came to our world: fear. Fear of the unknown, fear of what we could do to them, fear of us dominating their lives, their culture. There may be some jealousy about our tech, especially in areas where we are better at it than their mana tech. But "curiosity killed the cat" and all, some Drow will get over their misgivings and will want to exchange with us. I predict the younger Drow will be more eager, and older Drow may roll their eyes at their kids wearing t-shirts with logos of things they don't understand, speaking in words foreign to them, and Sharess forbid, riding those skateboards!
But given enough time, and if the Drow don't kill us or get killed by us, relations should normalize...at least one can only hope