1250 Monster list (revised); questions

[Rahab]

This list manages to cram in most of the MC models I want to play with, but, lacking a suitable harpy figure, I've added some other things. I'm still modeling and painting, but in the mean time, how well do you think this list will play in a casual environment?

Tyrant: LW&BS, devourer, shell armor; Biomancy
1 Guard

10 Termagant
Tervigon: cluster spine, extra spell; Biomancy

Carnifex: 2x devourer
Trygon
Tyranofex: spray acid, cluster spine, larvae

Hive Guard
Hive Guard

A few questions:

Is there any reason to put the hive guards together in one unit? Since I don't have any other elite choices, I'd think they'd be better spread out.

Would the codex spells be better for either the tyrant or tervigon? Biomancy seems like it's practically designed for our monstrous psykers, but paroxysm and catalyst look good too.

For the tyrant, is a melee weapon + ranged weapon the best route? This way he can use a "witchfire" spell as well as shoot the devourer, plus defend himself in close combat. I hope to keep the tyranofex in close support to thin things out with template attacks before charging in.

Without the extra points for Hive Commander, is it best for the trygon to crawl across the table rather than burrow? While I like the visual of it bursting up, every turn it isn't present something else is taking more fire.

Thanks.

[Jabberwocky]

Definitely run the Trygon up the board, he can easily get cover behind the T-Fex turn 1.

Biomancy is great, make sure you read into the other lores too though as against some armies, another lore might be better.

Splitting the Hive Guard should be fine in this case as they will be easy to keep in synapse anyway.