Holding tickets on Iceland ORD-CDG via KEF in Saga Premium Flex. I have lots of questions as to whether this is a smart move ( vs AA via LHR) but today's question is Iceland's unusual sizing limits for carry on. As a Saga Flex Premium, I get 2 carrry-ons, plus a personal, but the carry-on size is21.6 inches (55 cm) tall, 15.7 inches (40 cm) wide, and 7.8 inches (20 cm) deep (and 22lbs)

My questions are:
1. Are they likely to require me to check my single carry on of standard US size - 22 x 14 x 9 inches (56 x 36 x 23 cm) - Briggs Riley Baseline 22" -- which I've never had rejected in front cabin of any international carrier)?
2. Are they likely to require me to check my single carry on of standard international size - 21 x 15 x 9 (53.3 x 38.1 x 22.9) - BR Baseline GLOBAL 21" ?
3. If I need/want a Iceland compliant bag, who sells one that complies, with the 7.8 (20cm) depth being the most challenging dimension?

Thanks