I understand your plan but I'm not sure if this is the recommended way to achieve this. You may have reasons to use data pump but oracle recommends to do rolling upgrades of RAC as far as I know. So you would upgrade databases one by one. Even if you have new system. You could setup a similar 10g version in the new system first and do an upgrade after.
E.g. I would do manual in place upgrade and would follow [url https://support.oracle.com/epmos/faces/DocContentDisplay?_afrLoop=261093381551167&id=837570.1&_afrWindowMode=0&_adf.ctrl-state=lmcedwygq_134]Complete Checklist for Manual Upgrades to 11gR2 ID 837570.1 from MOS and this document has a TDE part. Which would advice you what to do with your encripted data and wallet.
There is a reference here to [url https://support.oracle.com/epmos/faces/DocContentDisplay?_afrLoop=264086096556673&id=1260584.1&_afrWindowMode=0&_adf.ctrl-state=lmcedwygq_156]Ora-28374 After Migration To 11.2.0.x from earlier releases 10gR2 or 11gR1 ID 1260584.1 that points you may have issues if you miss this previous step.
So if you still follow expdp/impdp path you may need this fix at the end. And yes you would need to copy the wallet to the new environment in this migration process I think. As you would do in the upgrade path as well.