Yes, 4x100 is 4 holes with PCD100
If 5x114.3 means 5 holes with PCD114.3
PCD means the holes distance spec.

Offset means how far/near the rim "face" from the center. Offset is important to know whether the rim would be too outside from fender or too inside.

Normally 8 holes PCD is 100/114.3, which means can accept both PCD. So if yours 4 holes, you also can use 8 holes rim.

Now only left the offset, if offset too little, the rim and tyre might too out and could hit fender.

Never heard the brand before, most probably is China made rim, like 99% rim out there.

Lenso and Advanti don't think there is imitation, others mostly just imitation. For other branded rim, original cost 3-4 times more expensive than imitation, but I also saw before a guy pay 4K for his supposedly original Japan rim, but actually is just imitation which normally people sell less than 1K. Unless you super trained to see original vs imitation, I highly advise against buying rim that have imitation in here.

Weight and price? Go to the shop and weight the rim, each design rim weight is different. Price also each shop selling is different, it's not fixed price like KFC.

Not sure the price, maybe around 800-1k.
Hard to find shop carrying these brands as most shops just go for China rims because it is much cheaper.