I'd get anything that is a "General Purpose Developer." I don't know if Rollei High Speed is considered general purpose or not, but if it is, the name is a bit confusing. It makes it sound something like Ilford Microphen (a special-purpose developer designed to use in push processing), even if it really is not.
If you are not using a stop bath, rinsing your film with agitation a few times (without exposing it, of course) should prevent almost all of the carry over from the developer, which will help your fixer out.
There is also hypo clearing agent (HCA), which comes after the fixer and before the wash. This makes washing more efficient, so that you can use a wash time half as long as you would have to use without the HCA. Water conservation is a very important consideration in the world today, and since photography already uses so much water, I try to be as circumspect as possible in my use of it. However, as Photo Engineer has pointed out, the use of HCA means that there is also the creation of however much load the HCA puts on the local water treatment facilities. Putting anything but water or human waste down the drain should always be considered closely, as a socially responsible rule of thumb. Call your local water district, and ask them whether there is any problem with dumping 20 g/L of sodium sulfite and 5 g/L of sodium bisulfite down the drain, and tell them how often and how much you would be dumping. If there is a problem, you can still use the HCA to save water, but you can bottle it up after use and dispose of it at a hazardous materials collection site, or cover it with mesh and let it evaporate outdoors.
This brings up the issue of chemical disposal. As mentioned above, check with your local waste water authority about your spent chemicals. The basic understanding for the low-volume home user to have here in the U.S.A. is that you should not dump used fixers or toners, and that you should try to make other solutions as neutral as is easily possible before dumping them, by mixing them with other spent chemicals. If in doubt, you can always take any photography chemical to a hazardous waste disposal site, where there will be trained people who know exactly how to handle the stuff. Even if something is fine to dump down the drain, this cannot hurt.