It sounds more like you have created a junior accessory dwelling unit which is a bit different than an accessory dwelling unit in the terms of size, juniors are no larger than 500 sq feet and is created using an existing bedroom.

I am currently a junior at Penn State University and I have just been gifted a large amount of money (in the 6 figures range) and I am looking to invest part of that money into real estate.

You're talking about carrying 5-15% in a junior lien position to an owner occupying buyer/borrower.....on a condo?  

Junior liens may survive in some states (e.g.

Unless there is loads of equity in the property, in the current market, junior mortgages are a difficult investment.Good luck 

I know that the the junior liens are wiped out from the foreclosure.  

The reason being the risk being high as 2nd lien or junior lien position.There are private lenders who would do HELOC on investment property; if they are first lien open-ended-mortgage. 

You also need to know Before you make an offer, about any other junior liens or debts, as the buyer will likely need to kick in some additional money to settle these, above what the first mtg holder will offer to settle them.

Top senior person gets say 25k and junior agent at bottom gets 8,000.Me as a principal commercial broker with my own firm representing buyers I get it all.

I agree it doesn't hurt to ask but in 25 years of doing this, I've yet to see anyone negotiate on a junior lien in a situation as you've described.Complicating matters is that you are not a party to the loan.