Any advice on buying a HUD home in full for cash (pros/cons) and what are the taxes that would go along with that for the seller the year they buy it (or breaks if there are any)?

no real difference in taxes you pay no matter how you buy the home, The main issue is if the loan is worth the value.
What interest would a home loan be ? Compared to value of money invested. For example right now I am getting about 5 percent on my investments ( just got my statement today) and if I could borrow money at 3 percent my money is making me more money in the bank