Many of the detections are generic (including avast) this make an FP a possibility, certainly more doubt.
Send the sample to virus@avast.com zipped and password protected with the password in email body, a link to this topic might help and possible false positive in the subject.
Or you can also add the file to the User Files (File, Add) section of the avast chest (if it isn't already in the chest) where it can do no harm and send it from there. A copy of the file/s will remain in the original location, so you will need to take further action and can remove/rename that.
Send it from the User Files section of the chest (select the file, right click, email to Alwil Software). It will be uploaded (not actually emailed) to avast when the next avast auto (or manual) update is done.
Once submitted, periodically scan the sample in the chest (every few days) and if it is no longer detected then it looks like it was an FP and has been corrected. That should hopefully resolve the detections on the temp .tmp files, normally I would suggest excluding the file/s from scans, but this is going to be difficult given the random naming issue.
Is there any settings in the program that can change the location for temp files, if so you could exclude that folder and .tmp files from being scanned, e.g. 'c:\Union_Temp\*.tmp' without the quotes, assuming you can change the default temp location for the program to Union_Temp, etc. The *.tmp bit would exclude all .tmp files using the * wildcard, care has to be taken to ensure you don't leave a big gap in security; hence the creation of a unique folder for union temp files and only excluding the .tmp file type..