I’m not going to tell anyone what to do with their bike, however, I will throw a couple things out there to consider…
1. Remove the clutch lever and inspect the pivot bushing.
If it is worn, loose, scored, or the hole has worn deeper, it will not engage the clutch correctly.
Also check to see if the rubber boot is torn, or jammed up inside the housing.
These alone can cause shifting issues.
2. Clutch fluid leaking out will never be seen on the floor, it will stick to the rear of the crankcase cover, IF the weep hole is clear and not clogged up (common)
3. Did you, or anyone else. Over fill the clutch master cylinder housing?
You don’t use the idiot lines outside by the window, you use the casting line inside the housing on the front wall.
Over filling can cause issues.
4. I would stop riding the bike you are unfamiliar with if you are hearing scraping, squeaking, or dragging noises from either wheel until it can be inspected by someone familiar with this model.
Everything you are describing sounds like a bike that has had the fluids neglected, and may have damaged the Clutch slave cylinder, and/or the left front brake caliper Secondary master cylinder assembly.
Put the bike on the centerstand and place your foot on the rear wheel and push down briskly one time and tell us how many rotations the wheel turns.
My guess will be one or less from your description of things.
If it does not spin freely at least two full rotations, I would suggest not riding the bike before you correct things, or risk damaging some very expensive parts, or getting tossed off the bike when the SMC locks up the rear wheel without warning.
You pay your dollar, you take your chances.
Good luck
Let us know what you find.