If you can find a 6 LT in stock (they're new and difficult to find in stock) then yes, no problem.
There are 8 temperature sensor headers on the Aquaero.
For the flow sensors, there are MPS type flow sensors but they need a straight connection in and out. The Aquaero can take a
High-Flow sensor on its 'Flow' header but you'll need to also order the
special cable as it's helpfully not included and is NOT the same as a fan plug.
For the second flow sensor (only any point if you're running two separate loops as they'll read the same in one loop unless you've got parallel paths) you've got two options.
1. The more expensive
High-Flow sensor with USB which connects by Aquabus instead of the flow cable. You'll probably want a 4-pin aquabus cable to connect it though. They include 3-pin aquabus cables but the 4th pin is power. With only 3-pin, you'd also need to connect USB to provide power.
2. Your other option is about the same cost, a bit more complex but gives you more. If you order a
PowerAdjust3 Standard version (Ultra not needed as the Aquaero controls it) you can connect it to the Aquaero by aquabus (3-pin is fine as it takes power from a molex) you can then connect a second of the cheaper high-flow sensor to the PowerAdjust's 'flow' port. The advantage in doing it this way is that you then have an extra 30W channel for running fans or pump. It's only capable of voltage control not PWM.
Both the PowerAdjust and the USB version of the High-Flow have temperature sensor header on them - doubt you'd need more than 8 but sometimes they're closer to what you want to monitor so make for neater wiring.