You could ask Pete to deliver one of letter+item-as-present at a time, by running DiiLC and playing two times in one day. You just need to switch Pete from one region to the other (as an example, two official DLCs, one from region KR and one from region JP, then put Pete in region KR and player slot in region JP, then run DiiLC, play the game, save the game, change the dlcsetting.xml to now put Pete in region JP and player slot in region KR, then run DiiLC, play the game, save the game, profit).

But as I have mentioned before, Wendell will not show up for the same player/character two times in a day, unless you change the date to the following day or use other player/character to receive the second one. And you need to do similar changes in the dlcsetting.xml for the pattern parts.

Hope that helps.