I will answer in order (I'm glad the discussion has started)
3) Ice Bolt and Ice Ring still affect Phoenixes (and by this time, a level 3 guild in the Red faction is usually already built), and the main heroes of the Red faction often have magic power 5-7 at level 2.

1. Phoenixes are not affected by cold.

2. The Red (this is, if I'm not mistaken, the upper faction) will not try to use attacking magic against Phoenixes; it will cast protection, curse, etc., and only when it sees that it can finish them off with an arrow, it will use it.
I always defeat the Red faction this way ;)

3. Hobbits, centaurs, fairies, dwarves... even three different stacks already reduce morale by 1..
The risk is significant because antimorale usually affects the hobbits.

4. At the beginning of the 2nd week, there is a part of your own native troops (ZD) and you can buy reinforcements for the faction... again, different troops... It's better to have 3 ZD, right? ;)
To meet the enemy...

5. Such a rush, as described by Gynnar, is IMHO beneficial when you know that the central faction is of your blood