yews are single sex plants so to get berries you need female forms and a male form either in your garden or near by.

You can also get fastigiate berberis, juniper, cypress, or consider bamboos or large grasses like miscanthus or stipa.
Or maybe matched obelisks of willow, hazel or rusted iron, covered with climbers like clematis for colour or sweet peas for scent, or ivy for a cheap evergreen option.
I would say, tall narrow pots with tall narrow plants in can be blown over very easily, I destroyed a treasured home-grown standard fuchsia that way.

There are three berberis, Helmond Pillar, red Pillar and a golden one. (Need regular watering)There's a fastigiate golden elm and a fastigiate ilex with very tiny leaves and an extremely narrow habit, Ilex crenata fastigiata. The last three will get tall if planted in the ground but should be OK in tubs for a while. The Helmond Pillar tends to get more bowl shaped with age but you can always cut off any branches more spreading than you want. Its supposed to grow to five feet but mine is just over that now, but its in the ground.

For tubs as small as yours I'd think the ilex would be the best of this lot although it isn't as attractive to look at.