We have 8 traveling in our group...
Ah, that adds to the picture! Splitting the coast amongst 8 would make a private guide more affordable. :O)
I would mention that while a guide can definitely be a bonus for certain attractions (Vatican Museums, Colosseum/Forum/Palatine) you don't really need one for everything if willing to do some reading in advance or using self-guided printed or audio tours. Still, as it looks like you haven't allowed much time for Rome (4 nights/3.5 days is my recommended minimum for that one), just hitting a couple of highlights is probably all you'll be able to squeeze into your 2 days, if those most-visited highlights are on your list. Keep in mind that heavy crowds and heat are likely to be factors on the physical wear-and-tear scale.
Florence is a gold mine for anyone interested in Renaissance art and architecture so unless those don't trip your collective triggers, please don't short it in favor of too many day trips out of town?