Everything will likely be metric. Cone wrenches will let you work on the hubs.

There are bike specific lubes but you can use other lubricants. WD-40 is not a good lubricant. It will quickly wash out of parts. For bearings you want something with higher viscosity to stick to the bearings. There are all sorts of chain lubes and many proponents of all sorts of formulations. It is religion for some. For bearings, I've used bearing, lithium, Phil Wood, Trek, etc. Doesn't really matter from my experience, just as long as it is decent grease and you relube when needed.

For chains, I'd recommend getting something specific for bike chains. You'll have to decide between wet and dry lubes here. An oil of any type might be your simplest option here. Don't fret over it too much though. Good chain maintenance is probably one of the nicest things you can do for your wallet. It will prolong the life of the chain, chainrings, and cogs.

If you are up to it, I'd recommend taking off the pedals, seat post and other small bolts to lube the threads on them. It may prevent some part seizing in the future. If you do it, I'd have someone check that you got everything back together correctly and with the right amount of torque.

I would think the brakes aren't cantilevers, but probably V-brakes or linear pull. A minor distinction, they all work via cable pull.

You should have plenty of range with those gears.