Hi Chris,
We take appropriate action internally to followup to any blocks on Marketo IP addresses, so there should be no requirement for action on your side unless we reach out to you. Regarding your second question, Email Suspended is a temporary 24-hour block, the field will stay marked true, but the block only lasts for 24 hours after the most recent Email Suspended Date. Email invalid will only be marked if a bounce message is received which indicates that the target address is no longer valid, or is inactive.