Hello, and welcome
Down to it:
Probably the most often built cabs for/by bass players is one of the Jack series.
Think Jack 10 or Jack 12 if portability/not lifting is the goal I would think, rather than a J15.
Is it only for live? When live, is it always with or without PA support? Is it for rehearsal as well?
That tempers any suggestions to some degree because, for example, if it were both live and rehearsal, then multiples of single cabs is the way to go, take what you need. eg 1 cab and head for rehearsal, or if bass is DI'ed and it's only for on stage sound when live, more cabs if not through PA.
Does your daughter most often than not turn down the treble, or does she prefer some treble?
Second guessing some answers, I would think a J12 or 2, one with tweeters wired with the on/half/off option, and the other cab sans tweeters.
Once the Jacks are dialled in, many reviews discuss the player having to define their technique some, as the Jacks are very articulate. They will reveal playing discrepancies.
While it could be used as such, and says so on the sales page, I don't see the DR series as bass cabs per se.
Having built 4 x DR250's for PA, I know they take a long time due to their complexity.
So you would also find the Jack series a more comfortable build, given your self described skill level.
There are some more complex cuts in Omni series, so, while it may end up being a better choice, it's not somewhere I would suggest a relative novice start.
The DRs, Omni's, and Jacks are all horn designs, so less power for the same or greater output.
The other option would be one of the Simplexx designs, much more like a standard cab with sides, back, baffle, top and bottom.
Due to better design, even the Simplexx series will perform better than many commercial offerings, at a lower unit cost.
What tools do you have?
Please ask as many questions as you need, we're here to help.
Hope this helps some...