Nice work planning ahead! I was hoping others would share their experiences however I did want to make sure you get your questions answered.
Traveling with a bike is not always that straight forward. I did it one season (2010) for 4 races and decided that I would pick races that I could drive to after that season. Those races took me to some awesome locations/countries/destinations so I am not complaining but it takes some planning to travel with your bike.
I would start with asking to borrow from a fellow club members. If not, Transition Triathlon can be a back up option for rental. I know Freshbike’s used to rent boxes but they are closed. Otherwise, I am not aware of other options.
Good luck with your effort! This is why it’s great to plan ahead!
While I have not used bikeflights, I know it is a good option. During race times, Tribike Transport will take your bike right to the race venue.
Anyway, if you are looking for a bike box (to pack up on your own or for bikeflight.com), you might want to post on the general forum. I am sure there are plenty of club members that have a bike box you could borrow right now since few are likely flying/racing right now.