To be honest it might take I while. I did this frame data semi automatically from ina tekken which is no longer available. In addition to Lei I need to do changes for all characters from season 2 and anna. I’ve created a page for Lei with source to a japanese site with frame data from him. For Tekken 7 on the PlayStation 4, a GameFAQs message board topic titled 'Julia hype topic!'
I made a frame data overlay for Tekken 7 pc users.
Here's an image explaining it: http://imgur.com/a/XvZCs
Here's a video: https://www.youtube.com/watch?v=L6jc3q0HnTw
It tells you the basic frame data of your last move and your opponents last move including frame advantage, hit type, startup, and the number of active frames.
Download it here: https://github.com/roguelike2d/TekkenBot/releases/
It's a standalone python launcher, so you should be able to just unzip and run the .exe and it'll automatically try to find your running Tekken7.exe process. Set your graphics settings to windowed or borderless mode, the overlay doesn't work if you're in fullscreen since it's technically a transparent window.
The program is still in the very early and untested stages, so if you have any problems, please report them.