You didn't mention what vehicle you are working on. Does it have a manual trans now? If so, pedals are in place. If not, then installing a pedal assembly from another vehicle will be a fairly major project in itself. Will you be able to fabricate new linkage? Perhaps use a cable system, or install hydraulic master/slave assembly?
Are you planning to swap the rear axle assembly for something newer? If so, then the E-brake problem is mostly solved. You will need to install a longer cable from your handle assembly to the new rear. The rear axle assembly that you install should be matched to the width of the car to minimize problems with the wheels/springs. Measure your stock axle drum to drum and start comparing to later offerings. Type into your browser: "rear axle width information". Several useful sites will pop up with measurements of many donor cars/trucks. You might even find something that matches your spring perch width/size. Also keep in mind what bolt pattern you have and what is offered. Do you want two different wheels on the car? Regarding driveshaft, You will likely need to have a new one made.
Some of the t-5 units have mechanical speedos, and, I think, the later elec types can be changed to mechanical with the correct pile-o-parts.
And you heard right, the t-5 has been used in numerous cars and small trucks. The application affects gear ratios, shifter location, overall length, (bellhousing) bolt pattern, input shaft design, and more.
Again, do a search for info. Hemmings (the magazine folks) did an indepth article on the t-5 some time ago and it should be required reading for anyone thinking of using the trans. This article will give a comprehensive list of vehicles using the t-5. Sorry that I do not have the article in front of me at this time to give date. However, do not abandon your info search until you read it!! If you truly cannot find it, PM me later.
Gary