Okay lots of questions so will try to answer as many as I can.
We do wear it at home too for praying the Qur'an or performing Salah (five times a day prayer).
I'm not fussed about taking it off at home, bras are uncomfortable whereas the headscarf is quite soft and light. If it is a really hot day and we've been on a day out during a heatwave then yes as I'd probably be hitting the shower next.
We cover our heads (men too) in the loo. See it's not just about women covering their beauty from men, it's also protection from the jinn (evil spirits which linger in dirty places like toilets - they run away when you read certain prayers or even by daily recitation of Qur'an to not bother humans).
The headscarf is also GREAT protection from the sun. It keeps you cooler. Same with the long black dress you may see us wear. Air flows in and out wonderfully.
I remember during a lesson at secondary school we were told covering top to bottom and wearing loose black is the best for sun protection. I smiked to myself as that's what I wore outside of school.
I also remember my language teacher staying out loud how she didn't get how so many girls were wearing head scarves and long dresses with long sleeves. She regularly wore vests. To be honest the heat or sun going directly on your skin is worse as you feel the direct heat as well as skin not being protected. I've known lots of people who have been ill for sure bathing and vowed to always use sun protection creams no matter what (even if they have to buy plastic as they're trying to go down the plastic free route). Covering the skin solves that without needing any creams.
As for a gift, a smile and hello is more than enough but I'd probably avoid home made snacks and just do something boring like a box of generic chocolates or something. I've been into making random little gift bags of alsorts like a fancy bag of crisps (or just one of those oversized normal crisps) with a drink in a glass bottle like schloer or feel good (Asda and Morrisons have them) with a small box of chocolates. It ends up only costs £3 or something and looks lightweight fancy.
And yes yes to the comments about women wearing head scarves before Muslims arrived in the UK. Even kids used to wear big hats and cover their arms in the summer. I remember seeing pics like that during history classes.
If buying dates for Ramadhan, as it's next week, make sure you check the label in case it's from occupied lands. I'd probably avoid it to be on the safe side.
Scrolling up through the comments in case I missed anything - no the headscarf doesn't feel bit and sweaty (choose a light fabric for summer and a heavier one for winter, all sorted) :)
However if you have long hair your feel sweaty from that but we'd do the same, roll it into a bun and good to go. My scarves never tend to stick to my neck or anything, as they're quite loose and flowy they go along with the breeze or if there's no breeze it rides of the bun and lands on your back. You get used to it to be honest and it's not an issue. I can say the same about the face veil too.
Don't feel bad asking, curiosity is all good and learning is better.