The bulk of this post concerns the $29 Pkard product from Thursby which is the first I found with explicit OS X 10.10 support. If this is bothering or interesting you, you may want to monitor this URL:
There is an active Citrix support thread on the “no valid certificates found” issue. Note: This entire post is basically google search bait designed to (hopefully) allow others struggling with the same issues to save a bit of time.
Using PIV smart cards for HHS VPN login with Mac OS X 10.10 Yosemite