No, it is not required or necessary.
You will need a visa which can be purchased upon arrival for $20.
You are free to stay as long as you'd like but your accommodation covers 10 days from October 13th-23rd
While English is a major language spoken in Gambia. Wolof is the official language and like any language it's not easy but here's a video to help familiarize yourself with it. https://youtu.be/-L0UGjFR16o
Yellow taxi's are all around Gambia with quite cheap prices.
It is hot so definitely more loose and flowy clothes are best. Because Gambia is predominantly Muslim, for women to be more covered during the day is expected but not required. Open-toed shoes are generally worn by everyone even those with less desirable feet, no one is judging.
There are definitely ATM's around and most restaurants and stores will accept most American cards though it is always a good idea to carry cash with you. In addition to the money that you bring to throw on the bride and groom, you can bring dollars and exchange for dalasis (Gambian money).
WhatsApp is the preferred method of communication with those coming from the States. Wifi is not readily available everywhere but with a local SIM card (which is free) you'll be able to access the internet at the times of your choosing.
An international converter is important as they don't use the same outlet type as America, they use the UK plug. Fans are a good investment as Africa is hot and portable electric fans can be purchased for quite cheap on Amazon or in stores. Portable chargers probably won't be necessary always but that is something that makes me feel more comfortable when travelling. Charcoal powder or tablets is a good idea to bring as well in the case that you eat something that upsets your stomach, it is the one of the more natural and easier ways to clear your stomach.
Roundtrip from NYC around $900
Around 55 Dalasi to 1USD
Yes absolutely! Please reach out to Keturah to make those arrangements.