regarding the value of the dolls now vs the price you bought them for.
that's always a double edged sword for me (not sure if that's the right expression).
sure, most want to maximize the profit from their purchase and have the item in question increase in value possibly so they could sell it someday but the price that one buys the item for needs to be considered too.
if i bought an item for 10$, and it's worth a 70$, it's still sort of worth 10$ to me although i know the value of it due to factors like rarity and popularity are higher. but hey, i went out, spent 10$ and am happy with the purchase, regardless of how popular i thought it would get.
now that it's popular, i could stick to selling it OR sticking to "i spent this much on it, had a fun and/or memorable experience getting it, it means a lot, i don't really care what it's going for (although of course, it's profit, but meh) because i bought it for this price, i am happy with my purchase, and am going to keep it until i feel like i could let it go without regret"
so while the doll rose in price tremendously, i do think it's totally up to you if you want to sell it. it was your purchase and you seem to really like the doll so it's up to you.
and honestly, in some cases, but i don't really like to do this, one could counter the people who are like "well, why don't you sell it because oh it's so valuable now?" with "well, why don't you sell some of your things that you like for some profit?" the argument here is a little faulty because they could just go "well, it's just a doll and it's one thing that costs a lot as opposed to various items" but i don't know. i kind of see it as "well, those items could add to the cost of it and you probably wouldn't really feel comfortable letting those go so why don't you let me do what i want with my things and i will let you do whatever you want with yours?"
my two cents on it anyway. D;