"Is there power to leverage IWD for Fistula Foundation?" -- yeah, I think that leveraging International Women's day to promote EA-endorsed, women-related charities is an awesome idea.

I think an important first step would be to collect a list of several highly-effective charities that are all on the theme of helping women.  Fistula Foundation is one, Family Empowerment Media is another, perhaps Population Services International is a third.  And I'm sure there are others out there!  Then, with your list of highly-effective women-oriented charities, you could put together some internet posts (to facebook, reddit, this very Forum, etc), containing:

• A basic EA pitch (the whole concept of maximizing effectiveness by tracking outcomes, and by giving internationally  where a dollar goes a long way) and link to further intro-to-EA resources.
• The list of charities you identified -- fun to give people multiple options because that gets people thinking about which they like more, and it also makes the post seem more objective/neutral (like Givewell's trusted recommendations) rather than just trying to market a single charity.
• A blurb on what each charity does, where they operate, etc.

Since International Women's Day is tomorrow, just slapping together a few reddit posts is probably the best we can do this year.  (For more thoughts on this, see this comment of mine on another EA Forum post about putting together a subreddit donation drive for International Women's Day.)  But in future years, we could have a whole The-Life-You-Can-Save-style website devoted to showcasing effective female-empowerment charities.  I am picturing something like Giving Green's EA-inspired recommendations for reducing carbon emissions.

I'm also excited about the broader idea that EA could promote targeted/thematic recommendations like this during other special days:

• Top climate charities on Earth Day?  I'm sure Giving Green and others are already doing this.
• Nuclear/AI X-risk causes on Petrov Day (although Petrov Day is a pretty niche holiday), or pandemic prevention donations on the anniversary of the polio vaccine or smallpox eradication?
• Great-power diplomacy stuff on Armistice/Veteran's Day?
• Progress Studies and prediction market / institutional-reform / approval-voting people could find plenty of holidays too, I'm sure.  (Maybe the Fourth of July?)  Same goes for the animal welfare wing of effective altruism.

EA already makes a bit of a coordinated marketing push every year on Giving Tuesday: people talk about their personal donations, organizations put out yearly updates, people participate in big charity matching drives, folks talk to their friends and family about the ideas of effective altruism.  I think we could score some nice low-hanging fruit by extending this strategy to International Women's Day and beyond.

"Are these types of straightforward, pull-at-the-heartstrings, charities and stories, an ideal "gateway drug" for newbies, into effective giving, and even into EA in general? " -- Of course a heartstring-pulling cause is more attractive than other causes, all things equal.  The question is whether this helps people on-ramp into learning about the EA mindset and eventually placing more weight on effectiveness than they did before.

I do think it helps to have some recommended charities that look like a normal kind of charity people have seen before, rather than immediately trying to sell people on crazy-sounding concepts, like "Actually, according to some complicated math, donations to AI alignment groups are 1000x more important than anything you normally associate with the word 'charity'."  Fistula Foundation might be particularly good, like you've mentioned, although Against Malaria Foundation does have the appeal of being able to say "for $5000 you can save a life (!!) on average", and tap into the drama and heroism of "saving a life".  Things like deworming don't even have that, which makes them a little more esoteric.

I also think it helps to present multiple charities and frame yourself as a charity evaluator -- this makes the endorsement seem more legit and it also helps get people into the EA mindset of making comparisons and prioritizing with limited resources.

"I'm also wondering... are there similar thoughts / attempts in regards to leveraging mass attention toward more effective aims?  I saw some attempts at getting BLM / police reform attention toward more-effective causes." -- There's a big difference in my mind between trying to nimbly harness recent news events like BLM, versus putting together a coordinated marketing message to capitalize on individual holidays like International Women's Day or promote EA's message to specific groups.  Leveraging news events can be very powerful, but also difficult, and  can sometimes backfire -- see much nuanced discussion here, for instance.  Leveraging thematic holidays is less powerful, but it seems really easy to do and has basically zero downside, making it a no-brainer.

3. I'm also wondering... are there similar thoughts / attempts in regards to leveraging mass attention toward more effective aims? 

(I saw some attempts at getting BLM / police reform attention toward more-effective causes; but I don't know how much attention these got outside of EA circles? Any other examples?)