Have you applied to Lancaster yet? If not, all applications are "open" because you apply to the university, not a college (different from Oxbridge and Durham in that way.)
When you have accepted an offer, you then HAVE TO choose two colleges that you would like to be allocated to. These are just preferences, you could in theory be placed in any one of the 8 undergrad colleges.
You would not lose your place if your 1st or 2nd choice colleges were full.