No, all ports in a port aggreagation have to be the same speed.
You may create the port aggreagation with any ports, including the management port. However it is suggested that the management port should be isolated for ensurance of management interface availability.
The 7 trunking modes directly map to bonding modes natively provided in Linux, please refer to the following links for details:
There's currently no limitation on the number of static routes allowed on a Qsan NAS units.
The loopback settings provides source address overwrite feature for Syslog and SMTP traffic sent out from Qsan NAS units. In cases where the dedicated Syslog server or SMTP server only accepts a specific source address, user may choose to overwrite the source address of Syslog and SMTP traffic sent out from ALL ports. Please notice this setting only works for Syslog and SMTP traffic, does not apply to or impact any other data service types. 
The default gateway is used for all traffic originated from the Qsan NAS, such as SNMP, SMTP, NTP, Rsync, Rplication…etc. In cases where the destination IP address does not exist in the routing table, the system will then try to reach the destination via the default gateway, on the designated LAN port.
No the Qsan NAS will not automatically check for any new firmware upgrades.
You may register yourself on our Qsan partner portal and after successful registration you will receive notifications of new firmware releases from Qsan.
You may then enter the partner portal to download the firmware and upgrade it via Web UI.
If the system is running stably, we would not suggest you to perform the firmware upgrade on your Qsan storage. With every new firmware download there is always a relese notes that comes with the firmware for you to check if the update or enhancement is necessary on your system, you may then decide whether the upgrade is necessary or not.
You may have to check the release notes that comes with the firmware for checking if any companion software need to be upgraded. At the end of the release notes there's a list of which companion software versions have to be used with the firmware.