I thought I could only root Lineage during install and not afterwards, that helps.
- I had to install the ROM, boot it up and set it up, then go back into TWRP and install GAPPS. If I installed them both at the same time, it would just sit there on the boot animation for hours and never boot. Not sure it's problem with TWRP or the ROM, but just something I noticed.
Very first time i tried installing Lineage this happened. Using the same files after reseting the Tab it worked the 2nd time. Figured it was something I did.
Everything is up and running and working fine.
One thing I noticed with TWRP, my 64GB SD card i'm using shows up as 199mb inside of TWRP.. I had to use a cheap 8GB SD Card to get it running, then switch back to the 64GB card. In Lineage it shows 64GB just fine, TWRP for whatever reason doesn't like it.
First time i tried to install (and got the boot animation screen forever) TWRP saw the card correctly, after that 199mb. Same card in 3 different computers.. 64gb and can see every file.