Congratulations on your offer! Applying for MQ's Leaders and Achievers early entry scheme is done through the mq.uac.edu.au portal, as opposed to the standard UAC portal, which is used primarily for ATAR-based applications. This means that receiving an offer through this scheme will not affect your other university applications. This extends to enrolling in the degree, although enrolling means that you have officially become an MQ student. While this technically means that your other university applications would be unaffected, you should keep in mind that you would need to cancel your enrolment if you end up receiving a better offer through the standard UAC application, so that you can then enrol and study the other degree.
In terms of receiving an offer through a standard UAC application, the same notion essentially applies, although with some important aspects to consider. If you receive an offer for a particular preference, you will not be considered for your preferences that are lower than that for which you received an offer, based on the reasonable assumption that you were made an offer for one of your more preferred degrees. For example, if you were made an offer for your second-highest preference, you will not be considered for your third, fourth, or fifth preferences. When this happens, you must ensure that you rearrange and/or change your preferences so that you can still be considered for other degrees.
I hope this helps!