Question about ranger spirits

I was playing around with a character builder and looking at the descriptions of skills.

I was wondering about spirits.

For example Fertile season goes something like:

create a spirit... for creatures within its range, every creature's maximum health and armor increases...

and muddy terrain:

create a spirit.. for creatures within its range, all creatures move 10% slower than normal...

My question is, from the wording of the skills it appears that the spirits affect everyone within their range, friendly and unfriendly... however from a logical point of view, it would make sense that buffing spirits like fertile season affects only allies (why would i want to cast it if it also gives all enemy a health boost??) and debuffing spirits like muddy terrain affect only foes...

I played a ranger during the last BWE but never actually used a spirit skill, so would be happy for a clarification from someone who used them or saw them in action

Although i havent yet played a ranger yet, i have quested with many and i thought the spirit was mostly used to "Pull" and enemy away from a cluster of enemies so you dont stirr up the bee-hive.

Nature Rituals affect everything that moves and attacks, be it friend, foe, pet, plant or char. They do have a range, and anything outside of that range doesn't get the affect.

Now I have a question: what about undead minions?

I'm not soo positive about undead minions, but what I do remember is that when I tested a Necro minion build In PvP When my minion was degenerating and I was almost dead when some ranger posted fertile season my health and the minions health went up... SOOO either fertile season helped me and the minion or some monk healed my minion coincidentially right when the ranger posted fertile season.

I got another question, this time about ranger preparations:

For example ignite arrows- for 12 seconds your arrows exploe on contact dealing 12 damage...

will the effect of preparations affect all skills/spells, or just normal attacks?

i.e. if i do use power shot while the preparation is active, will i deal the +10 damage from powershot and an additional +12 from ignite arrows?

Ignite Arrows will affect most if not all of your attack skills such as power strike, dual strike, etc.

and do preparations stack, i.e. if i activate ignite arrows and kindle arrows, will i get a bonus from both preparations?

any like categorized skill will not stack. Stances won't stack on stances..etc etc. You can however make a viable "stack" this way... ritual/stance/preparation/attack skill (unless..with something like Barrage that removes all preparations to use it)

To go even further... spells don't stack either. Two people casting same spell on same target..only one will take effect (the strongest spell level one).

Echoing a spell won't stack either...but it will let you cast it twice... on two different targets

this is not entirely true. enchantments and hexes will stack, so long as they are not the exact same enchantment or hex.

just to recap:
preparations do not stack. if you cast a preparation while another is currently running, the new one will override the old one.

preparations will affect all bow attacks including attack skills. Barrage is the exception as it will nullify any preparation currently running before you fire. Apply poison is the only preparation that affects all weapons including swords, wands, bows, etc.

nature rituals affect all creatures within range, including allies and foes. that is part of their balance and tactical use. the spirit is counted as a creature and can be killed but does not leave an exploitable corpse.