The spotter must declare its intention to spot before the IF attack is made, and its intention to also make or not make a weapon attack before the IF attack is made is this correct?
Correct. There first is required for the indirect fire attack to take place, and the second is required to determine if the spotter also attacks modifier is applied to the indirect fire attack.
I could not find anything in the rules as written that says this is illegal, the closest thing I found is that the spotter must declare that it is spotting before attacking.
If you don't add the spotter attacked modifier to the indirect fire, that itself is a declaration that the spotter is not firing. You can't say you the spotter is not attacking this turn, then attack with the spotter this turn.
I have also read that the spotter also gets a +1 penalty to its own attacks but could not find it in the rules, is this correct?
Attack Modifiers Table p.44 "Is from unit that is also spotting +1"
Do TAG and NARC special attacks count as an attack for the purpose of spotting? I.E a unit firing TAG or NARC would add a +1 in addition to the IF attack? Or does the +1 only count towards standard weapon attacks?
Yes. TAG, if successful, has an option that then negates the spotter attacked modifiers, but if it misses, you are stuck with the spotter having attacking and applying the spotter attacked modifier when it spots.
TAG also allows the spotter to break the spotter must not have attacked yet rule, beause the TAG itself says the unit spots. It's more specific and overrules the general rule. If you TAG a target successfully, you spot the target for indirect fire and ignore the spotter attacked modifier. If you unsuccessfully TAG the target, you spot the target, but have the spotter attacked modifier.
Using NARC is always going to add the spotter attacked modifier.
