eSIM or pocket WiFi?

It depends on the model and on the rental provider's terms, which state different maximums, so we do not quote a general number — ask the provider you plan to rent from. Worth remembering as well: even within the stated maximum, every connected device still draws from the same allowance when they are all working hard at once.

Yes, by turning on your phone's hotspot, provided the plan you bought permits it — a condition that varies by plan and is stated on each plan's page. Check it before buying if sharing is part of the plan, and bring a power bank, because a tethering phone drains noticeably faster.

It depends on whether you stay together. If you are together for the whole trip and some devices cannot take an eSIM, one shared unit makes sense. But if there are free days when you split up, whoever is not carrying it is offline all day — a far more common problem than speed. Look at the actual itinerary before deciding.

Every connected device loses the internet at the same moment — a single point of failure for the whole group. The defences are charging it fully every night, carrying a power bank on full days out, and making sure at least one person has their own connection as a fallback for calling a ride or reaching each other urgently.

Return terms differ by provider: some take the unit back at the airport, some ask you to post it, and some set a fixed return time. Read the terms before you collect it and plan the return around your flight, because a late return can carry additional charges under that provider's terms.

Yes, and many groups do exactly that: rent a shared unit to cover SIM-less tablets and laptops while you are together, and give each person a small eSIM for days apart or as a fallback when the rental's battery dies. The two work alongside each other without interfering.