Yes, you will need to apply for Vietnam eVisa at https://evisa.xuatnhapcanh.gov.vn/trang-chu-ttdt. You should apply a month before your flight to encounter for any problem it might have. The applications are usually processed within 5 days.
There are many affordable and nice hotels/airbnb in the city. We have put together an itinerary document for all the guests that are coming. The itinerary includes a list of hotels with affordable price and good location.
If possible, it would be great if you can reserve by the end of April so we can arrange seats for everyone.