You should review your license agreement with your account team. Licenses are typically per-user (where a user at a different IP counts as a separate user), but there are also connection limits for each user (each 'job' is a new connection as long as it is still around), and exceeding them can cause one user/IP to consume many licenses. 

If creating processes is slow, it might be worth looking into using Job Servers. This is a pool of processes that wait to handle 'job' requests. 

This is likely an issue with the OS - it shouldn't take that long to create a new process. It might be worth gathering an OS-level trace of your process while you do this to narrow down where the time is spent. Depending on platform, the trace can be gathered with strace, truss, Windows process monitor, or others.

From the documentation: "The best strategies for backing up databases are external backup and online backup." External backup involves external scripts (examples are included in the documentation, but do not show actually taking the backup, as that is done by 3rd party technology). This is generally the best way to take backups. Online backups can be configured and run from within Caché. All the various backup strategies, and details about how to use them, are available here:

https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=GCDI_b...

This is best to be handled by the WRC. Please contact support@intersystems.com and provide the full cconsole.log as well as the timing of your attempted startup and details of what you deleted, how, and when.

For what it's worth, my best hypothesis based on the snippets you provided is that you have custom startup code that isn't completing (possibly due to whatever you deleted), which is blocking startup from continuing.

Calling into IRIS won't work if the instance is hung, so the only way to detect that is something external to the instance. Take a look at 'iris qlist'. You can get more information from 'iris help qlist', but here are the basics:

Syntax:
        iris qlist
Description:
        Quick list InterSystems IRIS registry information for all instances, in a format suitable for parsing in command scripts.

To add to this, given that you're concerned with security and want to use TLS 1.2, you should strongly consider upgrading, as 2012.1.2 has a number of security issues that have been fixed over the years.

Are the two mirror members functioning as primary and backup? No members will even attempt to connect to the arbiter until you have a primary and an active backup (because that is the only situation where the arbiter is used). If you do have a primary and active backup, and they aren't connecting to the arbiter, I'd suggest contacting the WRC so that we can take a look at this with you.

Is the database journaled? Remote non-mirrored databases on mirrored ECP database servers can only be mounted read-write on the ECP application server (in this case the reporting async) if the database is NOT journaled on the database server. This is documented here: https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=GHA_mi...

"Select the database you want to access over this ECP channel from the list of remote databases. You can select both mirrored databases (databases listed as :mirror:mirror_name:mirror_DB_name) and nonmirrored databases (databases listed as :ds:DB_name); only mirrored databases remain accessible to the application server in the event of mirror failover. When the data server is a failover member, mirrored databases are added as read-write, and nonmirrored databases are added as read-only, if journaled, or read-write, if not journaled; when the data server is a DR async member, all databases are added as read-only."

I don't know the answer to this, but since you haven't gotten any responses here, I'd suggest opening a case with the WRC so someone can investigate it fully. Please include the $zv string from both instances involved, as well as the location of the installation (as I suspect that is relevant to the problem you're seeing).