I see you are using a Custom IPsec Policy. I would double and triple check them as Phase 1 isn't connecting. If all looks right try using the default profile and see it will connect
Generally no.... what are the ISPs for these setups? Are they using home routers? Almost always need to do some port forwarding/DMZ setup on the router.
A common cause of a phase 1 error is a mis-matching PSK. I have also had issues in the pasy with complex PSKs and issues with specific special characters. Perhaps try a simple PSK to being with like "password".
Are the public IPs directly on each WAN interface of each MX, or is one/both of them behind a NAT gateway?
Do you have the exact same IPSec policies set on both devices as well as the PSK? Also make sure you put in all of the private subnets you want to be able to traverse the tunnel in there because your screenshots show 192.168.8.x failing but you don't have that subnet in either VPN.