I found a magma pipe right out of the gate using the cheap trading depot hack
If that bothers you, just punching shallow exploratory shafts down the center of the area blocks is not very time consuming. Only takes 1 if you noted where the vent was on the embark map.
...I've only found enough hematite to make about ten pig iron bars. I have five miners that are all at or near legendary skill level just utterly decimating the first four z-levels desperately searching for ore.
Ore comes in veins, veins tend to be long. You don't need to expose every tile to find them - a diagonal tunnel every 10 or 15 tiles (or so) is a great way to start. (Multiples of "5", because 1 diagonal tunnel/5 tiles then exposes 100%.) Read the wiki, "exploratory mining" and "vein" for some ideas about how to cut some corners and still find what you're looking for.
Also, as Der' mentions, you want to do your exploration in layers that are promising - best place to start in the wiki is the above article, plus on the main page, under "guides" is a link to "The non-dwarf's guide to rock" (or something like) - start there. And "iron", to then follow links to the 3 ores that produce that. ID the layers - then punch down thru each area block (on a corner to avoid large clusters) to ID all the layers on your map.
You may be SOL, but with that info and some work (but less than you've been putting into it!), if it's there you'll find it.
All my wrestlers are elite champions and such
An elite weapon skill is deadly even with a (well-made) copper weapon - if you can overwhelm the orcs, you will one-strike them. The problem is that copper armour... well, sucks, and if the orcs get to swing a few times some will find their mark.
I'd go with obsidian swords and use the steel for helms and plate - 4/soldier. Layer that with copper chainmail and caps, plus the usual highboots, greaves, gauntlets and shields, and hope for the best. Arm/leg wounds can heal, where organs/brain/spine won't.
And/or marksdwarfs - stand-off battles from behind fortifications are usually a win.