Both items can be ordered from your IBD through Merry Sales.
For most riders square taper is still the best option, or would be the best option if Shimano still supported it. Shimano is obviously moving away this standard, along with the Octalink stuff. But other companies are moving in to support it. Cranks from Sugino, White Industries, Paul components, and Middleburn. Bottom Brackets from Phil, White Industries, IRD, Tange, and SKF.
My process for square taper cranks-clean all surfaces of the BB, grease threads and BB body, install and tighten to about 500 inch pounds. Clean spindle and crank hole with alcohol or degreaser, install and torque to about 350 inch pounds. DO NOT OVERTIGHTEN!
Also I’ve found teflon tape to work well on plumbing not so much on bikes.