Looking for pocket knife direction for my wife

Hello, I am just learning more about pocket knives as I suddenly developed an interest in them recently after trying to get one and finding it fell very short of expectations (some cheap Gerber?). I replaced it with a civivi element 2 and have been loving it, but the original buy was meant for my wife and I don't think that the element will fit their needs. Here are their list of needs:

• The main usage of the knife would be related to their ecological research, so mostly removing bark or cutting twigs for analysis. They also camp, but we do that together so we have the element 2 on hand for anything "heavier", but something to cut through paracord or other fine material. I don't know how this would impact the blade metal type, but expect saps and other organic stickies)
• She has small, weak little hands, so tall knives (>0.75") seem to be out of the question for comfortable handling
• 3" seems huge and unweildy to them. I'd think something in the 1-2 range would be more than enough I think?
• They are still uncomfortable with blades (again, bad experience with their first getting stuck open because of lack of hand strength), so something where their thumb isnt in the way of the blade while closing is a requirement of theirs (slide locks and buttons were okayed, back lock was acceptable). One handed opening is also preferred, as they may only have one hand to work with and, again, weak hands.

And, the kicker, they don't want to spend a lot of money on it (<$100 pretax).

What options could we be looking at?

PS were in VA, so I'm unsure if they can have an automatic (or assisted?) knife, but if it is an option I'd be down to get one/ask more questions about those.