If you are looking for more budget-based options on the arrival day because of Sister & family, how about Contempo Cafe (more 'adult' choices than park CS options) or Captain Cooks (start your Disney trip with a Dole Whip)!
I'm a little allergic to making TS ADRs on my arrival day because it's just tempting fate for a flight delay. I do hope your group can make dinner at Ohana one night, though; it's one of my favorites.
If you and Sister are not eating together the first night, you could go to the other extreme: just grab a snack when you arrive or in the park for a short afternoon, then make TS reservations for dinner at a signature. How about Artist Point, since you'll be at WL anyhow?
I'm a little allergic to making TS ADRs on my arrival day because it's just tempting fate for a flight delay. I do hope your group can make dinner at Ohana one night, though; it's one of my favorites.
If you and Sister are not eating together the first night, you could go to the other extreme: just grab a snack when you arrive or in the park for a short afternoon, then make TS reservations for dinner at a signature. How about Artist Point, since you'll be at WL anyhow?