According to the #46 Installation & Operation Instructions those lower hose to pipe connections were made before the hardnose was installed with the support bracket then being attached to the hardnose......so unless you can become a contortionist that's probably how it will have to get done. Might look into dropping the pipe assemblies and hoses together out the bottom after disconnecting from the #46 unit but I can't tell you for sure that will work.
To change a hose on my D6 9U with the #46 unit. I removed the pipe assembly from the HPU, bad idea!! After realizing that the hoses connected to the pipe assembly would not come out, I had to clean everything in place and re-assemble. Not a very easy thing to do lie-ing on your back under the machine. Those O-rings do not like to stay in place, and it is hard to hold the assembly in place and install those bolts blind.
If you remove the hose from the barbed end at the top ( leave the fitting on the cylinder easier to re-assemble something to push against). Remove the pan under the HPU. Using a long extention with a swivel and 9/16 socket remove the two bolts holding the hose fitting to the pipe assembly. Pull the hose out and replace. To re-install two people make it much faster but it can be done alone if you are ok with crawling in and out a few times. Dont forget to drain the oil from the tank and to have new o-rings for the plugs also. Not really a hard job to do but it is a pain in the behind, and the head also😈