A few questions about proposals

[3b48d273]

New to the platform, just completed my third job and had a few questions from more experienced freelancers:

1. If I see a job offer that has a large number of invites, I understand this means that they posted a job but also went searching for freelancers and sent them direct invites.  Should I skip sending a proposal for these jobs?   I don't have enough data to analyze, but it seems they have a much lower rate of viewing proposals.
2. I have a ton of open proposals for jobs that are very old... do they ever close down?  Client is last seen 20 days ago, that type of thing.  Will those connects be refunded?
3. I received a really nice review from the last job - is there some way to "star" this review so it will always show at the top?
4. I know this would probably vary per industry, but what is a good benchmark for conversion rate I should strive for?  3 out of 10 proposals will be viewed by the client, 1 our of every 3 views will result in a direct message, etc.
5. If I see for examples, 6 invites sent, 4 invites unanswered, and 2 interviewing, but no client last seen field, does this mean the client sent invites and 2 freelancers replied but the client has not yet seen the messages?  Or does "interviewing" mean there is some back and forth