Where can I sell clothes that I bought and never wore (or wore once)?
I see people post on some fb groups.. try joining the "Expats & Locals in Jordan" group or "EXPATS in Amman" and you can do that there
Where can I find a cheese platter with seasonal fruits?
The one from @Select Foods Shoppe is one of the best in Amman
Where can I buy 100% pure aloe vera gel , plus pure oils like jojoba, argan, coconut oil, and rose water as well?
I was surprised to see some of the oils you mentioned at @بزورية كباتيلو ، Bzuriyeh Kabatilo check it out
Where can I find sushi and alcohol?
@Living Room Loft has both sushi and alcohol and the atmosphere is really nicr
Where can I go for a nice sunny picnic (Amman or Dead Sea)?
@Panorama Dead Sea is one of the best spots to have a picnic on a sunny day. You can also sit at the restaurant and enjoy the food and the view
Where can I find completely non-smoking cafes/pubs/anything?
@Caffè Strada is non smoking but they also have a smoking area outdoors
Where can I find a good sushi place for a reasonable price?
Have you seen this blog from Tip n' Tag about sushi places in Amman?
http://blog.tipntag.com/the-weekender-sushi-burrito-breakdown/
Where can I buy jelly multi vitamins?
They have them at @Pharmacy 1 and definitely at @Kingdom Pharmacy