Hi, I need some help in a conversion I want to do on a tandem going from drop to flat bars.

I am visually impared and my new girlfriend is too short to be comfortable with drop bars and brifters, so I want to convert to flat bars, with intexed shifters, no twist grips.
Also looking for some pointers on small brake levers, she has small hands, not a lot of reach, if something like that even exists.

not sure if I have to change the front derailleur, anything else?
What shifters? what brake levers? would like to be able to use either disc or V brakes
The tandem is a 2008 RT3, has ultegra front triple, rear is 9 speed deore LX.

Just bought the bike, it has a weird setup, has a front stroker trail disc brake up front, stock rim brake still there. Dont know anything about this disc brake

Thank you for the help!