Any answers to my questions, please?

It's been a while since I played NWN1, but I believe it is indeed the attack bonus rating for multiple attacks if your char is capable of those extra attacks per round. The extra attacks have a lesser base attack ratings than the initial first attack.

IIRC the haste spell doubles your base attack speeds, which you can tell in combat ofc, but I don't recall if it reflects the change on the char sheet page. My memory isn't perfect, so I could be off also lol.
. Animal companions have multiple types of attacks. Usually two melee attacks that are the claws and a bite attack if they are a melee based animal. That makes 3 attacks for most four legged common animals, bears, wolves, boars, etc.

Oh and each attack has it's own roll to hit. So 1-3 can hit or miss. Pretty much just like the player character.

Though more exotic animals maybe have other types of attacks.

If the manual doesn't state it, then try googling dungeons and dragon monster manual. There may be fan sites that will explain much of this. The NWN games are also based on a certain edition of the DnD rulesets, so try looking for that version for NWN1.

For some reason, I don't recall Elanee's Dinosaur Animal Companion when I played it. I guess it really has been a long time. :)
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That is correct. A +10/+5 means that you get 2 attacks per round, one at +10 and another at +5. It's been a long time since I played NWN2, but the way Haste works in 3rd Edition is that you get another attack at your highest attack bonus, so using the example above, you'd get 3 attacks at +10/+10/+5.

The reason why Elanee's Dinosaur companion has such an odd looking attack block is because dinosaurs, like other monsters who have natural attacks, are attacking with 2 x Claw attacks and 1 x Bite attack, hence the different attack numbers. Under the stats you listed above, it's only getting one attack with each natural weapon. There are rare circumstances where you can give an animal companion (or monster) multiple attacks with its natural weapons, in which you'd get something like:

2x 1-3 +7 (Critical 19-20/2x)
2x 1-3 +7 (Critical 19-20/2x)
1x 2-8 +7 (Critical 19-20/2x)

@gog2002x Elanee's default animal companion is a badger. JMayer must have given Elanee the Dinosaur Animal Companion feat that replaces him with a deinonychus companion.

Thank you for the replies!

Yes I had given Elanee the Dinosaur Companion feat BTW!