some way to see the last steam freind/freinds you added?

steamfriends.info

edit: also you can add nicknames to your steam friends, highly recommend doing that

You can see when you added a friend by doing a trade offer with them, idk if there's another way.
I add nicknames or add friends to a category in the friends list menu, that way I know why I added them, and the name they had in that moment. That way I don't have to guess "Huh who is this guy" because they change their name every week.

You are able to see steam chats messages here https://help.steampowered.com/en/accountdata/GetFriendMessagesLog sadly they're deleted after 14 days so it's very limited.

some way to see every friend in order of added/how long they have been friends with me for?

https://steamladder.com/profile/76561198094803808/friends/friends_since/

https://steamhunters.com/profiles/76561198094803808/friends?sort=since

https://steamid.uk/profile/76561198094803808#FriendData

https://steamrep.com/profiles/76561198094803808#friendssection

but you need to make your friends list public for this to work

If it was recent, it should probably appear here: https://steamcommunity.com/my/myactivity
However, the log entry of this event might get removed if you aren't friends any more.