How does she know Jaheira's fertile?

Tempest nailed it on the head. Isobel doesn't know Jaheira's fertile, but has no reason to think otherwise. She's never seen a half-elf until she came to Amn, but has read enough and heard enough stories to know half-elves generally aren't infertile, subject to genetic disorders, vulnerable to disease, or any of the other usual problems associated with successful crossbreeds between different species. Isobel does bring a degree of scientific learning and awareness that's very rare anywhere in the Forgotten Realms outside of a very few places, and Isobel is from one of those places. I would like to emphasize that her Intelligence score is a little misleading: Isobel is educated as well as intelligent.

I can nonetheless see Jaheira attempting to regain control of the conversation by pointing that out as an assumption.

By the way, congratulations and please consult this before making any important decisions. ^.^

All work postponed until further notice due to my computer melting down last week. The repair shop says they should have it back in a couple of weeks, but Isobel's project is out of commission for now.

A Follower of Gond delayed by the failure of a machine?

Lets say I wanna change the pool of druid spells that for example, jaheira uses.. is there a file specific for her or the file is for all druids? Also which file would this one be ?? I tried to root it looking inside the editors but it lead me nowhere...

Also if someone could point a guide.. although I'm hoping this much will not be needed..

You mean, which ones show up on the spellbook page after a druid/she hits the right character level? There appears to be a specific one for her as well as one for all druids...it'll be a .2DA file of some sort, though I don't have the utilities installed on this latest reformat yet, so I can't give you the specific filename.

Yeah, I was talking about the 16 you get when ya fiddle with the arrows after double-clicking (btw, even if I TYPE in a number >16, it reverts to 1 when I click OK That's one of the major pissing-off points about this)

And I think Jarno raised an important point here

The number of inventory slots is 16, so at any time, the number of free inventory slots should (at max) be 16. Now, if the limits were raised (to say ... 32) then we'd have the ability to buy 32 non-stackable items as well (AT ONE TIME!!!) Which could cause problems (overflowing inventory/everything-falls-to-ground syndrome etc)

So, while I don't think everything falling to the ground would be game-breaking, I like to put this out:

Is there a way to change the limits of stackable items ONLY???
Or is there a way to increase how many come in 1 stack (eg 1 stack of arrows = 10 arrows ... can you increase that to say, 50)?? This probably won't work for potions though (you'll be FORCED to buy them in bulk )

Cheers,
Lol

If you're referring to the "40 arrows in a stack" limit, as I recall that's easily changed in the item header.  I don't have DLTCEP set up on this drive yet, though; can someone doublecheck that?

What about Ulgoth's Beard for the bad guys' headquarters? Is there an unused house there?

I don't think so, for most plausible interpretations of "unused." Maybe the sea tower? Reuse an existing map for a small area accessible from the base?

2nd idea: less a kit mod and more a desire to see the possibility of the pc becoming a vampire (evil only) after completing all the tasks for bhodi, would have similar progression to Valen; what do you think?

I think the proportion of the game that takes place outdoors during the day would kill either suspension of disbelief or the player's enjoyment, depending on how exactly this was handled.