I think if I lived in the city without a car, I'd probably get a Coccoro. It's super lightweight. It will last longer than (almost) any infant seat on the market, and since you can't have the convenience of popping the seat in and out of a base that's left in the car anyway - when there's no car to leave it in - I think you might as well skip the infant bucket stage.
The Coccoro also fits in tighter spaces compared to an infant seat, which is great when you have no idea which car it's going into next. I have used it in taxis a few times. It installs super fast with LATCH. It's a little more challenging with a seat belt, but not bad. You can get a Combi Flash stroller to go with it, but it also fits in a Universal Snap N Go.
And, if she gets lucky and has a petite child it could last quite a long time since it is a convertible and does rear-face and forward-face. It should last an average-sized toddler rear-facing to at least two, and forward facing another 6 months or a year after that. Even if they end up with a larger kid, a Coccoro will last them longer than an infant bucket and put off the time when they need a more standard-sized (or large-sized) convertible until later.
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