It's easy to do yourself - open up the CS and only select Morrowind
Now in the cell list - the one which gives you locations - select Seyda Neen and then select one of the dark elves - doesn't matter which one even if you get a female like Teleri - now zoom in on them and double click them to bring up their stat box - if female hit the button which turns them into male
Now on the right there will be a list of heads and hairs - this is where you start searching for the correct head and hair you want - they probably have ID's like BN_DE_Male_head01 or something like that so start with 1 save the box - tadah the head has changed but sadly #1 is probably not the one you want so double click again and keep going through the heads and hairs until you find the ones you want
Great you've found the ones you want - now write down their ID's - this was the whole point of doing this exercise to find their id's - in body parts find the ID's and double click on them - write down the nif paths they point to.
Ok now shut down the CS without saving and go get Wrye's vaccine - if you have wrye mash then it will be in a folder maybe the mopy one has it (I'm typing this away form my modding PC so can only guide you by memory) - drop that esp in with your other data files
Open up the CS select Morrowind and Better Heads (use the esp version they provide for modders not the esm version) - check to see what other esms Better Heads is dependent on - if your version is only for Morrowind then also select the GMST vaccine - if it has Tribunal and Bloodmoon then select those esm's and you don't need to worry about the vaccine
Done that - good - now make sure that Better Heads is selected as your active file - open it up and do a search through body parts until you find the head and hair id you want to change - it probably has an *at the start of the id - which will mean it has been changed - check the nif path - does it point to the BH folder? If yes double click on it and now type in the original file path for the nif to point to.
Do this for both the head and hair
Now save - wait you made a backup first didn't you
Once saved test it out by again finding a dark elf and giving them the head and hair id you like - if it shows up correctly well done - see modding isn't hard - if it doesn't well ok modding can have its frustrating moments but at least you gave it a go
If you really can't do this and can't find a mod that already does it - then post again and I'll do it for you - however I think you should give it a go first yourself - we can always use new modding addicts.