Having shipped a lot of gear a lot of places over the years I can concur with what has been said so far. If this is going to be a frequent thing, get a/ some pelican cases and use those. Don’t go cheap! You will need the lifetime warranty. The cases will stay structurally sound,but the wheels, handles, etc. Will get broken, and the occasional hole.
If this is a seldom/ one off any study box will do. The studier the box the more likely you will be able to use it to ship it all back. If you are using cases, use as big a zip tie as you can in the lock latches. Pack extra for the return trip. If you are using boxes, include heavy duty packing tape. It suck tying to find that on the way to the shipping place.
Take the bars of of all the saws. Put the bar and chain together in a plastic scabbard and pack them flat, preferably on the bottom. (Battery saws excel at shipping but you have to carry on the batteries or borrow/buy local). Use packing material to keep the saws stable. Use rope to keep ypur climbing gear stable.
Declare it as climbing equip and/or power tools. I would stay away from listing specifically as chainsaws. You are asking for attention.
Make a thorough inventory list, preferably with pictures and serial numbers where applicable. This will make any insurance claim easier if the while plan all goes to shit.
And Sean nailed it. Buy/ borrow pole tools local. Better yet wean your self away from them with few exceptions. You will be a better climber.
my .02
Tony