The speech should be about what you admire about your friend, and his partner. I wouldn't even mention you being trans unless that's a large part of your friendship.
Introduce yourself, tell a fun story that highlights what a great guy he is, explain how the couple is perfect for each other, and invite everyone to have a wonderful time.
May you always look back on the puppy months and remember the cuteness... and forget the middle of the night trips outside, the early mornings, the late nights, the chewed up [furniture | shoes | cords | etc.], accidents on the carpet, biting, scratching and constant ball of energy (between naps) of this cute little bundle of fur.
(I'm currently 10 weeks into puppy training my new mini goldendoodle and I'm optimistic that the worst is now behind us)
Nah, if you need to know why they've been vanquished to Australia you just need to look into their defense strategy.
This is the reason for the sly smile
When a female quokka with a joey in her pouch is pursued by a predator, she may drop her baby onto the ground; the joey produces noises which may serve to attract the predator's attention, while the mother escapes. https://en.m.wikipedia.org/wiki/Quokka#Description
My best friend came out when she was 34... and she almost exclusively dated women (cis or otherwise). I don't think she would have put the label 'lesbian' on herself, she was more pan, but I think the important thing is she did what felt right for her and what made her happy.
She did lose some friends, and some in her family had a very hard time learning to accept her, but she also found an amazing amount of love from the friends and family that did immediately, and without question, accepted her.
Stay safe, take care of yourself, and remember that no matter what the small minded people say, think or do, you still have people who love you and just want you to be you, and happy.