Is 8GB of RAM enough for running 2–3 VMs?

No, 8GB will cause constant swapping — get 16GB or more. The host needs 4GB, and each VM wants 2–4GB, totaling 10–16GB minimum. On 8GB, you’re overcommitted before the first VM boots, and your laptop will feel sluggish. 16GB is workable if you’re smart, but 32GB is better for future-proofing.