as of right now, it seems there is only the feature to post on LinkedIn. There is no interactivity between Adobe and LinkedIn. Maybe in the future with some other Updates that will come. Hope that helps.
Adobe Express content scheduler can only be used to schedule the posting of your content on different social media platforms at the same time. I think tagging specific accounts from Adobe Express Scheduler cannot be done since you are not using the specific platform physically and Adobe Express only have an access to post-scheduling and captioning from your connected accounts.
I hope that I answered your question or I gave help in some way.