I am puzzled by the interaction between Lifestyle and Downtime Activities, particularly as to lifestyle expenses.
One of the downtime options presented in the Player's Handbook, p. 187, is Researching, which expressly states:
For each day of research, you must spend 1 gp to cover your expenses. This cost is in addition to your normal lifestyle expenses . . . .
More downtime options appear in the Dungeon Master's Guide and Xanathar's Guide to Everything, including several that have associated gold-per-day costs. But none of them state that their costs are in addition to a PC's lifestyle expenses.
At the same time, certain downtime activities go out of their way to say lifestyle expenses are or might be covered during the activity. For example, Work, XGtE p. 134, contemplates an ability check the outcome of which determines what lifestyle one can maintain without cost during the activity. And Crafting, PHB p. 187, simply says:
While crafting, you can maintain a modest lifestyle without having to pay 1 gp per day, or a comfortable lifestyle at half the normal cost . . . .
In other words, the cost of Crafting subsumes one's lifestyle costs, at least to an extent. Adding to the confusion is the fact that the downtime options in XGtE are wholly optional "alternatives" that differ from options in the PHB and DMG. There is basically no consistency among them.
Even more confusing, the DMG says, at p. 128, that while engaged in Carousing, a PC "spends money as though maintaining a wealthy lifestyle . . . ." (Emphasis mine.) To my eyes, that "as though" is ambiguous. Does the PC spend money on her normal lifestyle and on the wealthy lifestyle necessary for Carousing? Or does the later subsume the former, as with the PHB's version of Crafting?
In short: which downtime activities cover a PC's lifestyle expenses while performing them, and which don't?