the bolt cutter is a good tool for mash-cutting the housing (and I always grind the housing ends flush and square with a bench grinder, whether using ferrules or not) but not for the cable itself, at least not for long...a true bicycle cable cutter will stay sharp much longer.
Otherwise, everything should play well together, the only possible glitch might be the clamps of the lever bodies on the Shimanos a hair big for the 25mm Belleri bars, but probably no biggie.
I have those "horrid" Weinmann levers on my '74 Grand Record, they came stock and I have no issues. Some of the earlier levers actually have slightly finer texture and cute little QR buttons that people actually pay big $$ for...imagine that!