Originally Posted by tatfiend

Quick release front wheels are normally 100mm spacing over the locknuts and should fit any front fork with that spacing. One possible difficulty is if the front fork ends are too thin not allowing the quick release to clamp down securely. Then slight shortening of the QR wheel's axle might be required.

Rear wheels with quick release wheels can vary in width over the bearing locknuts from 120mm to 135mm, 120mm to 130mm for road bikes generally speaking. Normal derailleur dropouts are generally the same whether for a bolt in wheel or a QR one so you should be able to replace a bolt on wheel with a quick release version. Same comments regarding dropout thickness apply as for the front wheel.

Replacing a 27" wheel with a 700C one will require lowering the brake pads about 4mm. If the brake calipers provide the adjustment range then there should be no problems. If not then different reach brakes may be required.