Yes, lots of maybe's
Cobbled together from a couple of scripts I use for scaling/saving screenshots.
This works (just) taking the OP requirements at face value. New image size is in line 9. New file takes the layer name. The only choice is the output folder and only once for any particular session.
What it does not do: lots & lots of things, eg. does not mark the image as clean.
I am sure all the clever guys will pull this into a thousand shards

edit: I can start that process myself: script works for me in linux, but crashes in Windows. Such is life
I put the missing escape in "\\" for windows, still crashes.
edit again: strangely, this works in a WinXP (virtual machine) with Gimp 2.8.4
I wonder what has changed from that old version?
edit again: Well the only way I can get my script working is by specifying an output path. (line 16) Obviously makes the export location dialog box redundant though.
#!/usr/bin/env python
#
from gimpfu import *
def save_to_files(timg, layer, outputFolder):
pdb.gimp_context_set_interpolation(INTERPOLATION_LANCZOS)
pdb.gimp_image_scale(timg, 270, 65)
pdb.gimp_image_convert_indexed(timg, 0, 0, 256, 0, 0, "" )
try:
# Save as GIF
# pdb.file_gif_save(timg, layer, outputFolder + "\\" + layer.name + ".gif", "raw_filename" ,0, 0, 0, 0 )
pdb.file_gif_save(timg, layer, "c:\\Users\\Public\\Pictures\\" + layer.name + ".gif" , "raw_filename" ,0, 0, 0, 0 )
except Exception as err:
gimp.message("Unexpected error: " + str(err))
register(
"python_fu_save_to_files",
"Save to files",
"Save the current layer into a GIF file",
"",
"Open source",
"2016",
"<Image>/Tools/Save to GIF",
"*",
[
(PF_DIRNAME, "outputFolder", "Output directory", ""),
],
[],
save_to_files)
main()