Hi,
I have never done a restore on Linux, but I think, it should be similar to AIX (Machines, OS & Informix version should be identical ).
copy the ixbar.<servernum>, sqlhosts, onconfig to $INFORMIXDIR/etc
The new box should have exactly the same LVs (if you are using the raw devices) as on original box. Check the TSM connectivity, you should have the correct parameters in dsm.sys and dsm.opt to connect you to the TSM server where you backed up the DB.Also worth checking sm_versions. Once the connectivity is proven, I think, you can run the restore command (onbar -r) or point in time restore.
I might be forgetting something, but you can still give it a go and fix the issue on the run. :-)
Nitin