^ all the addresses in your post are 7Fxxxx, they should be 7Exxxx.
The memory locations doc (posted in CL's original post) has a mistake with the addresses for that. TF is displaying the correct ones, though. Anyway, here's an idea of the code you'll want to use for the Epoch:
Step 1:
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Category Memory Copy
Command Memory Copy
Variant 4E
Copy to 7E0290
Data: 00000000A0
The four 00 bytes are the X and Y coords (2 bytes each) If you leave it like that it'll place the Epoch at 0,0 on the map (very upper-left corner) The A0 is the Epoch status byte. A0 is for upgraded, and IIRC 80 is for the original Epoch.
Here's an easy method to get the Epoch X and Y coords you want to use without having to calculate stuff. In ZSNES, fly the Epoch to where you want it to be parked in your event code. Then open the cheat search and hit Size 1 byte, Format Hex, Comparative Search, and press Start. Then press the View button. Scroll to 7E0290 and you'll see the 4 coordinates bytes.
Let's say I do this, and see the following:
7E0290 A8
7E0291 01
7EE292 10
7E0293 01
Then instead of the 00000000A0 above, enter A8011001A0.
Step 2:
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Assignment
Value-to-Mem
Variant 4B
Value 1F0
Store to 7E029F
Width Two Byte
The value box is where you put the map you want the Epoch to be on. In this case it is 1F0, 1000 AD map. Use 1F1 for 600 AD, 1F2 for 2300 AD, etc. etc.
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If you put in A8011001A0 for Data in Step 1, and 1F0 for Value in Step 2, it'll park a winged Epoch right in front of Crono's house.
BTW, don't forget, if you don't where the Epoch is you can press Select to view the zoomed out map and look for the flashing yellow dot.
Have fun.