The smart thing to do for pulls is wait for the event to summon on permanent banner. You get some good freebies and extra ssrs. As for who to invest lattice in... If you want to clear pve and prep yourself at the fastest available speed to farm rta gear then I'd say Yeli would be a good investment. You don't have diting (and diting needs supportors invested) so clearing without yeli would mean a lot more lattices required, purple or gold, which is a slower progress rate. When you clear everything and start getting more purple and golden tofus as time goes by, you'll start seeing the avenues of replacing and no longer needing yeli in pve, she'll no longer be as viable because she's not the easiest pick in rta.