Any upgrades of special units stay on the character sheet, whether the unit is on the board or not.

All of your units attack simultaneously (you can also choose not to attack with some of them). So two level 1 units that have one attack upgrade each, can kill a level 2 unit. Or a level 3 unit that has two attack upgrades (remember, level 3 units and the crabs are the only ones that can have more than one attack upgrade at any one time), can attack and kill one level 1 unit and one influence marker. It`s up to the player.

You can use the Crab's special ability, ATTACK, in whatever manner you want. You do not have to use all of the unit's attacks. You are also free to assign the attacks to multiple units in the same zone, if possible.  

No, the Attack may be activated only once per turn. Two skulls mean you can do more damage.

Yes, they can. Units are always allowed to attack, until they are removed from the board at the end of the activation phase. 

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Removing casualties: Influence markers killed during the attack are removed
immediately. Special units killed during the attack are removed AFTER all attacks
have been performed by all players for that turn. Special units can always perform
their attacks, even if they were killed by another player earlier in that turn
( It is recommended to place the special unit on its side after a defeat to indicate
that it has already been killed that turn).
The killed influence markers and units are always returned to their owners after
all attacks have been resolved.

You can bluff, you do not have to pay and use the actions, especially when you have seen the actions of other players before you. You may also place your action marker just to prevent other players from doing so on their turn.

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Spend 2 population tokens to move any number of influence markers
and/or special units from one region to any other region.

By ANY number, we mean that you are able to decide how many are moved from one region to another. You are not required to move them all. When we say any OTHER region, we mean only ONE region. Units or markers moved in this fashion are not allowed to be split up. 

Yes.

If there is no region token in a region, then units or influence markers may not be moved or placed there. These region are considered completely excluded from the current game.

Your question has been added to the FAQ:
http://thelordoftheicegarden.com/pan-lodowego-ogrodu-faq

Many thanks for your help! (^_^)

New abilities may only be placed on the blank spots of the character sheet, or to replace previously bought abilities. You cannot replace the printed abilities. A unit of level 1 or 2 may not have two identical abilities (Crab is the exception, that is why it costs 2 reputation more to summon any number of Crabs).

You need to have two Making actions in order to summon units of two different levels in one turn.

Yes, you can Make more and your reputation will not drop any further.

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"Each of these three actions may be taken once, and in any order.”

The Making field allows you to do all three of these actions once, in any order, for each action marker aassigned.

The -2 reputation modifier is per summon, so it is recommended to try and summon several crabs at once.

one crab= - 3
two crabs= -4
three crabs= -5

They are more expensive as they have two attack as printed abilities.

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Spend 2 population tokens to move any number of influence markers
and/or special units from one region to any other region.

By ANY number, we mean that you are able to decide how many are moved from one region to another. You are not required to move them all. When we say any OTHER region, we mean only ONE region. Units or markers moved in this fashion are not allowed to be split up. Sorry for the confusion.

Vuko always has to move to a different region. However there is one exception: if the player with least reputation has influence in only one region, already occupied by Vuko, then Vuko does NOT move.

For example, the player with the least reputation has influence in two regions. One region has 8 influence and the other has 6 influence. If Vuko is already in the region with 8 influence, he must move to the region with 6 influence.