I can't see a problem. The sibling threshold is around €40,000 i think so with 4 of you that should cover the value of the house if it's around €160,000.
If it's more, she is liable for the extra, about 20percent i think (i'd look up the figures but i'm rushing) so say house is 200,000, she has to pay 20percent of the 40,000 (just a rough example)
It shouldn't impact any inheritance to your kids, different thing/thresholds.
Stamp duty will be payable and solicitors fees
HTH
Ladybird