And obvs there's a 10k limit on small claims.

Technically that's not true.

There is no monetary limit for going through county court for money claim.

That £10k is threshold for a case being automatically assigned to the small claims track. If the threshold is breached, the case is assigned to the fast track or multi track. In rare cases, one can ask to make an exception.

What your friend is purpose could be considered as an abuse of court process which could lead to all the 3 cases being consolidated together, exposure to the costs order, or any other actions that a judge deems reasonable.

Honestly, if your friend thinks her case is strong, then they want fast/multi track as it means solicitor costs could be claimed from the other side.