I know this might have been answered but:

Does Dawnstrike work with the Equinox and Winterflame? or just with Solstice Strike?

It does indeed, however it works like any other damage dealing focus, it diminishes 10% per level. Also, it only affects the first nuke component of Winter's Flame (which essentially makes it not worth using a Fire of Dawn proc on).

To be specific, Fire of Dawn has the following affect:
Rime Crystals - 50%
Equinox Burn - 60%
Winter's Flame (Fire Component) - 70%
Dawnstrike - 100%

In essence, if you're going to continue to use Dawnstrike, your best bet is to just use Dawnstrike again for the chance of triggering Fire of Dawn again.

So with anguish level foci, am I right in thinking that dawnstrike is still our best nuke to use?

Ancient chloro seems our best heal too. Sad really.

So with anguish level foci, am I right in thinking that dawnstrike is still our best nuke to use?

Ancient chloro seems our best heal too. Sad really.

I am still using both of these, mostly for their efficiencies with current focus effects. The new spells aren't bad progression-wise, it will just be some time before I acquire focus effects that make using them worthwhile.

With Demiplane damage focuses and Anguish spell haste/mana preservation focuses, these are the nukes I use under different circumstances (leaving out Cloudburst Hail when it is unsafe to use):


<table border="1"><!--
--><thead><tr><th></th><th colspan="2" align="center">Priority:</th></tr><tr><th></th><th>Damage per second</th><th>Damage per mana</th></thead><!--
--><tbody><tr><td>Fire resistant, 1 mob</td><td><b>Rime Crystals+Cloudburst Hail</b></td><td><b>Ancient Glacier Frost</b></td></tr><!--
--><tbody><tr><td>Fire resistant, 2+ mobs</td><td><b>Rime Crystals+Cloudburst Hail</b></td><td><b>Cloudburst Hail</b></td></tr><!--
--><tr><td>Cold resistant</td><td><b>Equinox Burn</b></td><td><b>Dawnstrike</b></td></tr><!--
--><tr><td>Weak to fire+cold, 1 mob</td><td><b>Winter's Flame+Cloudburst Hail</b></td><td><b>Dawnstrike</b></td></tr><!--
--><tr><td>Weak to fire+cold, 2+ mobs</td><td><b>Winter's Flame+Cloudburst Hail</b></td><td><b>Dawnstrike+Cloudburst Hail</b></td></tr><!--
--></tbody></table>

As for heals, I use Ancient Chlorobon most of the time, throwing in an occasional Adrenaline Surge if I have mana to spare (mostly for the chance at a Vie autocast).