IDK, the first two "seem" OK to me; the third one appears sketchy. The first thing I'd do is get them out of the 2x2s and start with @QuintupleSovereign's advice. Then get them weighed and measured. With severe wear the weight might be an issue. Steve
While there are many copies of the Spanish coins, the weights and appearance of the coins you picture lead me to think they are genuine. The English piece appears to be a half crown of King William III, but its condition is such that it lacks the numismatic value the Spanish coins may have. The costs of sending these coins out for verification and authentication may make doing so not worthwhile. They do have considerable historical significance and are worth keeping and possibly displaying (especially for anyone who attended the College of William and Mary). Of course I am no expert so that is just my two bits worth of advice.
I concur with the view that they are probably not fake - if I had any doubts it would be on the first one, but the weight is right, so probably just corroded. Just to add, the William III halfcrown 1697 was minted in York, which should make it more interesting. (You can make out the letter "y" beneath the bust.)