Dual carb setups have fallen out of favor as they are more complex and costly, and don't add much if any performance. They were somewhat popular for a few years. The theory was better performance at both low and high rpm's compared to a single carb, sort of like a 4 barrel carb on an old V8 compared to a 2 barrel. Maybe better emissions in theory. Or maybe the marketing guys though they were cool and would sell more bikes...
Shop labor for a fork seal replacement is less than an hour, probably only 1/2 hour if your shop does not have a 1 hour minimum. Bring them the fork leg off the bike. Probably $40 or so for labor, plus a new fork seal ($20+-), and they will want to change the fork oil ($20+- from the shop). Most old bikes need a special tool to disassemble the forks.
Clutch cables are usually pretty cheap. See if Motion Pro has one for your bike. If the cable is old, might as well just put in a new one. Make sure you route the new cable correctly. Some bikes do have stiff clutches, but if the cable is not routed right that can make the pull harder.
Hard starting when hot can be several things, but one of the first things to check is your valve clearances. On a bike, they tighten up with wear and heat. If they are too tight, the valves don't close all the way when the motor gets hot. You lose compression and the motor won't fire. Some bikes are jetted too lean, and that also can cause a problem with hot start, but check your valve clearances.