Toughness of an enemy
As far as I can tell, there is no difference between them.
I searched for the changelog, and the features in their webpage and there is no evidence of that.
They only put everything under BG2 engine and add few tweaks(ie. as lockpick in BG1 do not give EXP, they had to set it to work properly).
Those good old games usually are very difficult to play, and this game in special, at the beginning it is kind of hard, because you have almost none equipment, and your team stats are almost the same as the enemy (sometimes lower). Making the winner of the fight the ones that attack first.
If you try to play the Baldur's Gate 1 as it is, without the mods, and feel it is easier, it must be because there is a mod someone set on your EasyTutu making it harder.
Yet, you can use some mods to eases it a bit.
This one may hurt your gameplay when low level, the randomness of the encounter may set more enemies than what you are used and are supposed to fight at early stages.
Look for EasyTutu Spawn Randomizer in the Easytutu feature site. It's an addon which will help you to not get beaten by six wyverns early on.
About the Wolves
Wolf(on BG2) NWOLF
HP: 24/24 XP: 65
Armor Class Resistances
Base 7 Fire 0% Cold 0%
Crushing 0 Missile 0 Electricity 0% Acid 0%
Piercing 0 Slashing 0 Magic 0%
Magical fire 0% Magical cold 0%
THAC0: 18 Slashing 0% Piercing 0%
Number of Attacks: 1 Crushing 0% Missile 0%
Abilities Morale Saving Throws
Str 18/00 Int 16 Morale 10 Death 13 Breath 16
Dex 9 Wis 9 Breaking Point 5 Wands 15 Spells 16
Con 9 Cha 9 Recovery Time 60 Polymorph 14
Lore 0 Luck 0
Thief Skills Fatigue 0
Hide In Shadows 0% Stealth 0% Intoxication 0
Set Traps 0% Disarm Traps 0%
Pick Locks 0% Pick Pockets 0%
Detect Illusions 0%
The str 18/00 changes for each kind of wolf, I found with 18/ 0, 18/40 and 15
I found some math:
With THAC0 18 it should hit against Imoen's 6AC about (12/20) 60% of the time.
STR - Damage / THAC0 Bonus for Playable Characters
15 str = no bonuses
16 str = +1 to damage
17 str = + 1 thac0 and damage
18 str = +1 thac0, +2 to damage
18/01-50 = +1 thac0, +3 to damage
18/51-75 = +2 thac0, +3 to damage
18/76-90 = +2 thac0, +4 to damage
18/91-99 = +2 thac0, +5 to damage
18/00 = +3 thac0, +6 to damage
I did not found the in game damage stats
But I found the Wolves(The first ones, as the stats above) come equiped with 3 kind weapons(?!?!?).
*the bears have B1-8
As the Monster compendium(1989 ver.2) show 2-5 (1d4+1) damage for the fist Wolf, and other sources as (1d6+1) - I don't know which one was used for the Baldur's Gate - I think that the p1-4 could be the dice rolled to damage calculation.
Depending on the spawned Wolf you could be one hit easily without crit, and if the strength damage bonus count for creatures you can get * near death * with de p1-4 hit too.