Some problem with email and general question

Hi! I’ve some problem with the email system of Buddypress and some other question:

1) after the registration of the users the emails with the activation link arrive very slowly and on behalf of wordpress like in the screenshot1. How can I solve it?

2) when users click on the activation link, a pop-up appears: “the link leads to a suspicious site, are you sure you want to proceed?” (screenshot3)
this is strange because my site is classified as a secure site (screenshot 2). What could be the problem?

3) how can I change the captcha, removing that with the addition? (screenshot 4)

4) I’ve a problem with the creation of posts. When I click on the “send update” button, my post disappears and I have to reload the page to see it. How can I solve this problem?

5) how can I add widget at the top of my activity page? (screenshot5)

6) I want to make a multilingual website. Which plugin do you reccomend? I want to translate everything inside my website, slider and small details included.

7) How can I add this code with code snippets plugin? ( https://archived.seventhqueen.com/sweetdate/article/add-profile-information-member-name-members-directory )

Thank you very much for support!