Can a witch use their (not the host bodies) abilities while possessing another through Magic Jar? Can they cackle and Hex and cast, etc?
My idea is to have a BBEG witch hop into the bodies of her followers, while attacking a town the PCs would have to defend. Her familiar would carry the Magic Jar Item and be invisible but within range if she needed to "evacuate".
Is this possible? Keeping in mind her followers would all be willing vessels and she'd have plenty of time to do this as they plan the attack.
Also, does the witches original body have to be within the range of the new body or just the magic jar itself?
I thought you were referencing the Beast Bonded Witch Archetype's Twin Soul ability (@10th level) which doesn't use a receptacle.
Anyways, Magic Jar says:
You keep your... class... and mental abilities. The body retains its... natural abilities, and automatic abilities. ...You can't choose to activate the body's extraordinary or supernatural abilities.
Class abilities includes spellcasting and hexes. If the form (i.e. dog) doesn't have the physical capability, you may not be able to manipulate spell components or complete somatic gestures - similar to Polymorph.
re: your last question, it does seem reasonable that all direct effects of a spell are limited by it's stated range, but I believe that only the transfer itself is limited by range: this part of Magic Jar makes explicit that it envisions you using the spell in ways where the target body/the receptacle/your body are temporarily out of range of the spell...
If the host body is slain beyond the range of the spell, both you and the host die. Any life force with nowhere to go is treated as slain. If the spell ends while you are in the magic jar, you return to your body (or die if your body is out of range or destroyed). If the spell ends while you are in a host, you return to your body (or die, if it is out of range of your current position), and the soul in the magic jar returns to its body (or dies if it is out of range).
The spell range is only invoked where specifically mentioned in the spell, i.e. for the actual transfer of souls. Once the transfer is complete, the bodies/receptacle can move wherever they want to (even to other planes), although the above section describes the consequence of what happens if they are out of range.
Since it is an effect that can be dispelled, that implies there is ongoing spell effect over distance (which could plausibly be subject to range limitation), but since it is giving specific repurcussions for the spell ending while you had been using it beyond the range of the spell, I think the intent is pretty clear, even if it seems to have violated the norms on spell ranges somewhat. I actually think this is similar to Summoning spells, they have a stated range which applies to where the creature appears when it is cast, and that creature can be dispelled, but the Summoned creature shouldn't actually be given a range/perimeter on where it can go during the duration - although that isn't stated clearly for Summons AFAIK.
OK I sort of figured the range thing meant you could go out of range and take the risks.
I made a few changes to my BBEG and made her a changeling with the Dreamweaver archetype.
My question NOW is can her Dream Possession ability be dispelled? It is a supernatural ability that functions LIKE magic Jar but it's not magic jar and supernatural abilities can not be dispeled with dispel magic. It seems this makes it very hard to "kick her out" of a host but negates the need for an item to "jar" into. It's very much liek the Twin Soudl ability you mentioned.
Dream Possession (Su): At 10th level, a dreamweaver can take control of any creature that is sleeping because of her slumber hex or a spell she cast. This effect functions as magic jar, using the witch's familiar acting as the soul receptacle. A Will save negates either effect (DC equal to that of the witch's hex). Whether or not the save is successful, a creature cannot be the target of this hex again for 1 day. This ability replaces the witch's hex gained at 10th level.
The body left behind somewhere is an Achilles' Heel. Unless the Witch is Beast Bonded.
The situation is that the PCs will be colonizing a new land and the BBEG is the spiritual leader of several tribes who are trying to drive the invaders out of their homes. It's got a lot of grey areas for RP and plot hooks.
She won't be lacking in willing vessels among her people or guards to watch over her when she is helpless.
She won't be Beast Bonded, she'll be a changeling with Dreamweaver archetype.
Yes. Your class abilities (including spellcasting) carry over into your new body. Keep in mind that you may not be able to cast certain spells if your new body doesn't have hands for somatic components, a voicebox for verbal, or any of the material components.
I've used this to great effect.
Another good question would be if ongoing buffs follow "you" into your new body.