2000 Tyranids

[Larkii]

I am sure I will be corrected if I am wrong (and that would be good) but since the Zoans can deploy separately, I think they do not have to have exactly the same psychic attacks. Even giving one of them Synapse would greatly increase the coverage. Also is is clear that lurking 'Nids can hold objectives?

[Kelmon]

Yes, only one Zoantrope left behind with just synapse for a little gaunt squad increases the coverage a lot ... the rest invested in attacking, flanking, close combat killing machines and you have a nice little tyranid army ...

[Crystalmonkey]

Also is is clear that lurking 'Nids can hold objectives?

In the codex, under the section for lurking (bold added for emphasis):

"Alternatively the brood may Lurk. This means it will remain stationary that turn but may fire its weapons as normal. Lurking units that are not Monstrous Creatures add +1 to any cover saves they may benefit from. Lurking Tyranids may not claim objectives or hold table quarters."