Hello!
Welcome to hitched.
Don't be dismayed that no one has posted back to you, this manly forum is quite new and not as well known as wedding planning (WP), i would copy and post your concerns etc. on the wedding planning forum, we do have a few chaps around.
We're all very nice and won't bite!
As for your post...
The BestM speech is about your life together, silly things you've done, memorable things..when he was there for you. It doesn't have to be full of jokes it's just a summary of your brother for the guests and to congratulate him and his new wife.
The stag do can be pretty much anything - activity days which inc. paintballing, quad biking etc. plus a night out. There are loads (and I mean loads) of companies that can get you good prices for these things whereever you want them ...either UK or abroad (but this will probably restrict numbers due to money at the mo).
Good luck
…always got her eye on biscuits 