What I love about old gear is that you can pair it with newer gear to get what you're missing functionally.
For applications that older laptops can't tolerate, I tend to spin up a vm or, in a pinch, set up a server (for multiple connections) dedicated to presenting. That way the old gear is just a jumping off point to better gear.
I do see where doing a heavily html5'd page will cause older laptops to have issues, though even in that case I'd try puppy linux or something similar/small and see if that can handle the load. If it's just presenting on BBB, don't need AD.
As a matter of fact, my BBB is integrated into my NextCloud instance so almost everything is on the server-side anyway, meaning if you can slim down the OS requirements and what's needed to browser-based access (mail, bbb, etc.), you can really make that 8 gig ram and 2 threads work for you better ;)
Would love to hear your thoughts, and would also be able to help with the integration. Only one docker -it command needed to change the secret to be nice and secure, too!
-Jack