easy jetの予約について

可能ですが、変更しない覚悟で予約すべき

確か保険はすでに加入しているはずなので、不要だと思います。
普通の保険(航空機の場合はほぼ死亡)。

変更に関しては、
www.easyjet.com/EN/Book/importantnotes.html

Refunds, flight transfers, and name changes
easyJet does not issue refunds. In exceptional
circumstances, however, easyJet will consider
issuing a credit in the event of the bereavement
of an immediate family member

Once you have made your easyJet booking, names
of passengers and flight details may be changed
on payment of an administration fee per passenger,
per one-way flight. In addition, if there is a
difference between the original fare paid and the
current fare available at the time the change is
made, the customer will be liable for the increase
in fare.

Click here for more details.
　
で詳細をご覧ください。