1) If I am playing one of the grand pianos on the keyboard i can record that into ableton right, and it will be there in ableton as MIDI then if I wanted edit? What lead do i need to connect from the keyboard into an audio interface or straight into laptop?

You connect the USB “To Host” port to your computer via a USB cable.

2) Can i turn off instruments on the keyboard and just use this a USB Midi controller for sounds i might have on my laptop?

Yes.
You can setup and play the internal CP88 sounds with an entirely different setup for external use. The CPs feature a 4-Zone Master Keyboard Control Function that lets you Control External devices via both USB and standard 5-pin MIDI Out.

What you setup and arrange on the CP is for the CP. Just because you split upper/lower on the CP, what you are doing Out via MIDI is setup separately. If you wish to just play external devices turn Local Control = Off; this allows you to use the CP88/73 keybed as a 4-Zone Master Controller. It can simultaneously control external tone generators via USB (computer/laptop/tablet) and hardware modules via standard 5-pin MIDI. This 4-zone Setup is for external use.

Your configurations are stored and recallable — no matter how complex a combination of internal, external devices.

You can construct complex setups that include all options... Unused sections of the CP front panel can be configured as remote control for external zones. The Knobs and Switches send CC messages.

3) The update of firmware, so i can have the cp7 grand piano is quite easy right, and via a USB stick which i have filled from th ecomputer with the update and put into the keyboard?

Correct. The firmware download includes detailed instructions along with the actual program file. Read through the instructions twice... once before you do it, and a second time as you execute the firmware update.

thanks so much for your reply. going to slightly rephrase question 2.

Can i turn off the in built sounds on the CP88 and use the CP88 as just a midi controller, using plug in sounds in ableton for example and play on the cp88, just like a USB powered Midi controller keyboard which has no built in sounds?

Yes.