If Winona has had any contact with guinea pigs in the past 3 weeks, then she needs to be quarentined. You can put them together first for floor time, then clean out the cage really good before putting them in together. Any rumblestrutting, mounting, nipping is normal. Seperate them for a little while if there is any bloodshed. There is a chance that they will remember eachother, but I'm not sure how good a pig's longterm memory is. You can never ask too many questions.
Good luck!