since u said pre-re defense but in renewal, with original file its not possible because the def is difference.
For example cotton shirt in pre-re def=1 but in renewal def=10.
Theres no problem to load all the maps since that is client side. even with pre-re setting should can access renewal maps as long as the client support it.
And theres a lot of items with different effect in pre-re and re.
In renewal there is rebalance and so much more, so its already different compare to pre-re which is already stopped long time ago.
If you asked is it possible, should be. But with more works, more time, more headache, etc.