Das bin ich:

 They are around 4 months old.

The boys cannot be spayed if they are younger than 10-12 months old here in Romania.

The girls can be spayed at 5-6 months if the vet are confident in doing the surgery.

How should we pair them? 

There's nothing like sisterly love, and this pair are living proof.
Born in an apartment building’s basement but lovingly raised by their foster mum since they were about 6 weeks old, sisters Hermione and Harriet are two 4 months old sociable girls, healthy and playful, good tempered and well mannered.  

Hermione is the calico🤍🧡🩶 She is the master of all toys and could win a gold medal in the Olympic Games if allowed to compete. Fast and intelligent, lean and slender like a lizard, she's such a joy to have around. She’s also very feminine and sweet and when play is over, she loves to come sleep in your lap or stuck to your chest.
Harriet is the grey tigress 🩶🤍. She's small and fast, very curious, always the first to investigate a new corner in the house, a cardboard box or a new toy. Agile like a squirrell, extra-fluffy and extra-funny, she makes adorable little gremlin sounds when running and playing.
When the batteries run low, both sisters drop asleep, usually une upon the other.

They are both fully de-wormed, vaccinated and perfectly litter-trained.
They get along well with other cats and dogs as they are fostered by a family with multiple animals.