At last I was able to add support for the language[Answering for the sake of others who might face this issue]. It seems there was some issue with the font I tried earlier( though it was looking fine in PC and was known to be working in other models of mobiles ). Steps followed
Downloaded relevant ttf and otf fonts to SD card
Rebooted to TWRP
The answer can be found on Reddit
If I remember correctly (from a discussion long ago), Google's ROMs are transferred about 2.2 times across the sideload. To make the progress bar add up to 100%, they said "2.2 times the file size equals 100%". Our ZIPs are transferred just once, so the final progress is at about 47% with a success. The xfer seems ...
FYI: I'm currently using eelo which is a fork of LineageOS with MigroG
You don't have to worry about installing MicroG. Just download and flash a fork of LineageOS which already has MicroG installed (like eelo)
And the signature spoofing you were talking about is already there in MicroG services(enabled by default) You don't have to worry about it..
First of all... MAKE SURE YOU HAVE DOWNLOADED THE CORRECT ROM FOR YOUR DEVICE..
Backup important files
Go to recovery and select wipe
select the things you wanna wipe.. except the usb-otg thing
After wiping.. go to advance(from home page of twrp)
select adb sideload
Make sure adb is installed on your pc
in cmd(admin) type ...
alot of people are going google and gapps free now. do it like this.
install fdroid store, then install aurora store from fdroid.
aurora store is to install apps from google playstore.
most playstore apps will run fine.. some wont, look for alternatives.