PoAs must have a wet signature.  You may refer to this link for a recent discussion on this topic: https://accountants-community.intuit.com/questions/1749935-e-signature-for-form-2848

As for electronic signature for F.8878 and F.8879, the requirements are clearly spelled out in this FAQ: https://www.irs.gov/e-file-providers/frequently-asked-questions-for-irs-efile-signature-authorizatio...

Sounds like RightSignature does offer KBA as an option to comply with the IRS' requirements but you may run into problems with MFJ according to this article.  You may need to inquire with Citrix directly if this can be overcome somehow: https://support.citrix.com/article/CTX227153