Recover oracle 10g database from old data files

There is no need to copy the files - there is an ASM "trick" that does exactly what you want to do with no interruption in service. When ASM rebalances a disk, it maintains a list of viable LUNS for each block independently of the LUN on which it presently lives. It also won't drop a disk on which there are active blocks without rebalancing elsewhere - but it will mark it as not a viable home for rebalancing!

Once you have used oracleasm to make the new LUNs visible to ASM, you just issue the single command (forgive syntax, off the top of my head)

alter diskgroup my_dg add disk 'new1', 'new2', 'new3' drop disk old1, old2, old3;

Then sit back and wait. ASM will hot-relocate each block from the old storage to the new, laying them out nicely on the way, and drop the old disks when the operation completes. I/O will be a bit higher, but your users probably won't notice a thing.

As for your ORACLE_HOME, I'm afraid switching that will require a (brief) outage.

I don't have the 10g version of Express Edition installed, but if it is like the 11g version, then your first question is answered in the comments section of the Backup.bat file itself.

For 11g this means the comments indicate that No cleanup script is needed because the script automatically keeps two backups in the Flash Recovery Area. Whether there is a better method or not will depend on what your recovery requirements are.