Internet redundancy for both inbound and outbound traffic

[ShenSimps]

So we need to replace our very much outdated internet load balancer and firewall.  We are considering using a pair of highly-available Meraki MX84's for this and I am trying to figure out how could configure fail-over between two internet connections.  We have a primary fiber internet connection and a backup cable modem. 

Is it possible to configure the mx firewall to NAT inbound traffic from either internet connection for services hosted on our network?  How could we setup DNS ensure that internal services are available on either connection? 

We greatly appreciate any help and advice!

[Nash]

Use a dynamic DNS provider and duplicate the config on any 1:1 NATs so they've got IPs available on both WANs.

If you're using port-forwarding, use dynamic DNS on the virtual uplink IPs.

[PhilipDAth]

Yes you can create inbound NATs on both circuits.

https://documentation.meraki.com/MX/NAT_and_Port_Forwarding/Port_Forwarding_and_NAT_Rules_on_the_MX 

As well as the option mentioned by @Nash , you could also use a DNS service like Amazon AWS Route 53 which lets you configure health checks and perform automatic DNS failover.

https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover.html