2. Once my device arrives, I want to test the recovery seed (pretend I lost my device, and use the recovery seed to recover my wallet). As I understand, if I do this with the Ledger, the seed and thus my device will be worthless afterwards; whereas with the Trezor this is possible without problems. Correct?
No, that isn't correct. If anything, the ledger is slightly more secure when restoring the seed as you enter it all on the device itself... you don't type anything into your computer, so keyloggers will be unable to record your seed words. Downside is that it takes a LONG time and a LOT of button pressing
The Trezor attempts to work around this in one of two ways... Firstly, using the standard restore, you type the words in random order... and are occasionally asked to type in a randomly displayed word that is NOT part of your seed. The idea being to confuse keyloggers with "junk" data.
Secondly, Trezor have implemented an "advanced recovery" mode, where you get the 3x3 grid of letters displayed on the device screen and click on the 3x3 grid on the PC screen to enter the appropriate letter sequences. Nice and secure, but like the Ledger system... takes a LONG time and a lot of mouse clicks
Both of the devices are solid hardware wallets. I would not hesitate to recommend either to someone looking to secure their coins.