Warning. This is going to be a long post. @Felldownabackdonhole if you want to DM me to ask for any more info I'm happy to help. I've been to Disney so many times and I'm currently planning my next trip.
Flights - have a look at aer lingus and compare it to Virgin and BA. you can get direct flights from some airports with Aer lingus or have a stopover in Dublin if you want to clear customs in Dublin instead of Orlando as Orlando customs can be hell. But just make sure you review your luggage allowance for both the domestic flight to Dublin and then the international flight to Orlando because it's different luggage sizes. But I have found aer lingus to be about half the price of virgin
Luggage - pay in advance for at least 1 extra suitcase to come home with you as you will buy lots whilst over there. Pack that extra suitcase inside another suitcase for the flight out.
Transport - Car hire has become a bigger expensive since covid as a lot of car hire companies have had to sell cars to keep them going so have increased there prices. If you intend to stay "onsite" in Disney for most of the time you won't need a car as there is buses and the skyliner since you are staying at Caribbean Beach. If you need to travel somewhere by car use Uber or Lyft. Disney's bus from the airport is stopping in January. Mears are currently looking at replacing the Disney bus for a price but nothing has been announced yet. Alternatively you have Uber or Lyft or normal taxis.
Hotel - what type of room are you booking? Look online at websites like touring plans to get an idea of where your room may be compared to the lobby, the quick service restaurant, the table service restaurant (was closed but will be open very soon), the skyliner terminal for Epcot or Hollywood Studios, the pools and the bus stops for Magic Kingdom, Animal Kingdom, Disney Springs and the water parks. Some types of rooms are only in certain buildings. For example the pirate themed rooms are in the building furthest from the lobby and restaurants but close to the skyliner terminal.
Meals - you will be getting an amount of money as dining credit instead of the previous dining plan. The dining credit will not cover all your meals, only a portion but it does help. There is a massive variety of food at Disney. It's is not just burgers and fries. You will always find something to eat. There is quick service restaurants which is like takeout (queue and take a tray to your seat) or table service (sit down meal with servers), and also snack carts. Meals can be huge so consider sharing meals or ordering kids meals.
There are some character dining meals which are more expensive but currently they are still distanced due to covid, and there is no Winnie the Pooh character meal at the moment (but could change)
As you are going in June there is a chance the Epcot Flower and Garden festival will still be running (this year ran till beginning of July). There will be lots of food booths where you can try different food from around the world and a lot of vegetarian options as Disney will be showcasing the fruit and veg that they grow themselves.
There is also lots of different types of restaurants at each hotel so branch out and try the different ones.
Planning - currently there is no fast passes to book rides for certain days, no news if that will change or if they will implement a paid version of it like they have started in Paris. You do have to make a reservation for each day you want to go to the park, however once it hits 2pm you can always hop to another park if you have park hopper tickets if you would like a change of scenery. There is a way to check if a park is at capacity and if they are accepting hopping or not but I'm not sure how to check that.
Some table service restaurants you will need to book 60 days in advance (used to be 180 days) as they can book up fast. For restaurants in the parks make sure to book the restaurant for the day you intend to be in that park (no point booking a lunch at Epcot on the day you intend to be at Magic Kingdom).
Also consider booking a breakfast inside a park before the park opens as it means you may be able to go around the park and maybe ride some rides after your breakfast before the park fully opens.
As an on-site guest you will be able to visit any park 30 mins before it opens. This is the replacement for extra magic hours. Unless you stay at a deluxe resort you won't be able to stay after the park closes.
Characters - currently there is no proper meet and greets. Instead characters will appear in places at random times for social distanced meet and greets. They may be on a balcony, or in a section of the garden etc. Also there is no official big parades, instead they do things called cavalcades which are mini parades that occur more frequently throughout the day so people don't all wait around for the 1 parade of the day.
Covid rules - currently masks are to be worn on all transport at Disney (bus, skyliner, boat, monorail) for every guest age 2 and up. For people who are double jabbed they don't not have to wear a mask if you don't want to the rest of the time. For people (including children) who are not double jabbed, they have to wear face masks indoors unless sitting to eat and in ride queues. So you may not have to wear a mask but your child will. Consider if you want to make it easier on your child and wear a mask the same time as them.
Also masks are currently needed in the airports and on the planes. No clue if that will change.
Watch lots of YouTube videos. Search for tours of Caribbean beach resort. WDW 4K on YouTube are good for walking videos around parks and hotels without talking. TimTracker has good vlogs about the parks and is currently doing staycations at hotels so you can see what they are like.
Join Its Orlando Time on Facebook, and google websites like touring plans, kenny the pirate, undercover tourist and WDW prep school.