Hi,
First of all read the below note if you see issue in patching .
822379 - Known problems with Support Packages in SAP NW 7.0x AS ABAP
1) Is it necessary to upgrade kernel level? If yes then up to what level?
Sap always suggest you to use latest tp,r3trans and SPAM so that you dont have known issues while applying support pack.
So you can take of the above statement by applying kernel and SPAM/SAINT patch for your release.
2) How to find out dependent sw components?
Just try to generate the stack file from solution manager or you can go in SMP and try to dowload the below patch and check there dependency.
3) Is there need to increase patch level of other sw components( SAP_BASIS,SAP_ABAP etc) If yes then up to what level?
I dont think but will have to check more for your release but many team apply only HR patches to get them perform end of year tasks. Dont see any issue in that but still need to check the pre condition of the SAP-HR
4) Is it necessry to increase patch level of other HR related sw sub components (SAP_HRCAR,SAP_HRCAT etc)?
The get upgraded when you apply EA-HR and SAP-HR patch.
5) Detailed procedure?
Can use SPAM to apply them.
Thanks
Rishi Abrol