I feel that Froggy's original question is still unanswered: if the meaning one wishes to convey is specifically 'She is here [now and is to remain] here for a while', how is this done in Welsh? Would one perhaps use the future tense, on the grounds that the sbel implicitly extends beyond the present moment into the future?
You can use either the present or the future with bod, really, although the future could also mean that she has yet to arrive:
- Mae/Bydd hi yma am sbel
Generally there is enough context around these things to make the meaning clear - we cannot show that very well on Duo where there is generally just one sentence being given at a time.