Hi @Tucker1,
Just to confirm, did I answer your original question? If so, could you please mark my previous reply as accepted solution?
For SMS in sequences there is a request here: https://community.hubspot.com/t5/HubSpot-Ideas/SMS-Texting-Capability-With-Sequences/idi-p/311952
For LinkedIn messages, you would have to create a task in the sequence, they can’t be sent directly from the sequence.
If this answers your last question, please also accept it as a solution.
Best regards!