The transaction log for database 'SolarWindsOrion' is full due to 'XTP_CHECKPOINT'
I am wondering what the best course of action is and if there is
  anything else i need to do to prevent this issue in the future once
  resolved.


As Kin Shah mentioned, 


  To get you out, change the log size to unlimited, run a checkpoint and
  take a log backup (probably few). Why cap the tlog size ?


Setting the log size to unlimited and not capping it at 2GB whilst taking regular log backups should fix your problem.



In your case, that was not possible yet.


  I get the same error when trying to change the size to unlimited.


The error


  The transaction log for database 'SolarWindsOrion' is full due to
  'XTP_CHECKPOINT'"


A temporary solution could be adding another log file, taking a log backup &amp; changing the size of the original log file.

An example of creating the log file, taking a log backup, changing the size to unlimited and removing the log file.

USE [master]
GO
ALTER DATABASE [DB_NAME] ADD LOG FILE ( NAME = N'DB_log2', FILENAME = N'F:\Log1\DB_log02.ldf' , SIZE = 65536KB , FILEGROWTH = 65536KB );
GO
ALTER DATABASE [DB_NAME] MODIFY FILE ( NAME = N'DB_log', MAXSIZE = UNLIMITED);
GO
BACKUP LOG [DB_NAME] TO DISK = '\\LogBackupLocation\DB_LogIssue.trn';
USE [DB_NAME]
GO
ALTER DATABASE [DB_NAME]  REMOVE FILE [DB_log2]
GO

--The file 'DB_log2' has been removed.



  That seems to have done the trick. As far as best approach moving
  forward. Now that i have the transnational backups happening every
  30secs (as originally planned) should that prevent this issue from
  happening in the future?


Depends on the Always On Availability Group settings and the size of some transactions if you keep the max size at 2GB. 

Setting the max size of your log file to unlimited and on a separate log drive where it could grow should be best.
As far as scheduling log backups go, 30 seconds should be pretty good.