Norman Huefner, DDS

Actually you have an advantage to correcting a chipped upper front tooth with direct composite bonding, as your lower teeth don't hit hard on it as with patients who have normal bite or overbite.
However, it seems that your teeth are not equal in size and width, and you may want to see a cosmetic dentist to have porcelain veneers on your front two teeth.  That would correct the chipping problem, and the color and size descrepancy.

I disagree with your dentist.  Go to an orthodontist and I am absolutely convinced that he will recommend orthodontics (either invisalign or braces) to correct your spacing and crookedness of your teeth.
If you decide not to get orthodontics, then you could have either direct composite bonding between your front two teeth to close the gap, or porcelain veneers on your front four teeth to make them all straight and proper proportion (your lateral incisors are much smaller than your central incisors). 

It is difficult to remove a fixed bridge that has been cemented without destroying it.  Techniques that some dentists use to tap a fixed bridge off all intact run the risk of fracturing the underlying teeth.  However, the bridge can be removed, just that you may not be able to use it again.
Can the false tooth (dentists call this a "pontic") be removed off of a fixed bridge?  Yes it can.  The dentist can usually drill off the pontic without destroying the other two teeth on the bridge.
If that was done, yes, you could then have a dental implant to replace the pontic.

First of all, you do have gingivitis and that is probably why your space developed.  So, the first order for you is see your dentist, have your teeth professionally cleaned, and then start flossing and brushing daily. 
This will help your gum recession from occuring in other areas of your mouth, but may not cause your gums to return to their normal height.  Unfortunately, surgical procedures to add gums around the papilla (where you are missing some gum tissue) is not very successful.  If it gets worse you may elect to have porcelain veneers or bonding to make your teeth wider in the area of the gum recession, thereby hiding the spaces (cosmetic dentists call this "black holes" or "black triangles").

You have a severe malocclusion and there is no "quick fix" for treating it, but it can and should be treated.  I highly recommend you see an orthodontist, a dentist who is a specialist at problems such as yours.  You age isn't necessarily a problem.