I recently moved into a house that had an oil tank removed that was underneath a front walkway. I've now taken on the project of replacing the walkway however there's one thing i'm concerned about- settlement of back-filled dirt under my new walkway. After i got the walkway excavated and compacted, I added 2-4" clean stone as a sub foundation. I have also inserted 1/2" rebar to 'bridge" the area that may settle so that may project isn't ruined 5-10 years from now. I'll also space out mesh reinforcement between control joints throughout the walkway (there will be no control joints along the 20' section of rebar).

I have a few questions below,

1) I assume the mesh must be separated where the control joints are placed, correct?

2) I plan to lay brick on top of the 4" concrete foundation and then cut through where the control joints are placed and fill with poly sand. Is this the way it should be done?

3) I'm planning to use 4000psi concrete- should I ask for 5% air?

4) These are old 1920's bricks that will absorb a lot of water- i'm assuming they should be sealed after being mortared to the concrete to avoid water pulling through or is this not necessary?

5) Can joints be mortared as i'm laying the brick or will that have to be done a few days later?

Here are some photos,