We are doing a similar level of renovation, and ourselves. We are not in any ways professionals (although DH is an electrical engineer who used to work in building services, so has some clue about some things0.
if you plan to live there, one room at a time is definitely the way to go. Stops you going mad and feeling like you are living in complete squalor. Also you see progress more quickly, which a huge motivator to keep going.
We changed the oil heating to gas first. Admittedly, it was mostly because the water was never warm with the oil system, so a few moths of tepid showers speeded that up.
Then we got a structural engineer in, getting him to 'futureproof' his drawings, in case we do add an extension.
Then kitchen, but theoretically starting the wiring as well. We have the new consumer unit under the stairs, with all of the wires ready to go when we are moving in to other rooms. This is a really VERY slow way of doing it, becuase you have to spend ages thinking about all the rooms and what might end up there in future (audio, internet, heat thermostats, a consideration to a system that allows motion sensors) even though we are ages away from doing anything in those rooms.
We are doing the windows room by room as well, and doors.
If you do the room-by-room approach, you have to make sure you make really good friends with trademen. We aren't using that many, but have a plasterer who is happy to slot in a room for us between two 'bigger' jobs. Likewise windows, we have ordered for the whole house, and can either pay the company a bit for storage, or pay a bit more to have them manufactured to order (which is what we are doing, just in case things change). We also have a builder who will do structural work for us, again happy to do small jobs.
But yes, getting a quote for someone to do it all for you is worth it as well. At least then you have an upfront guide to cost, as opposed to our emergency dashes to screwfix that cost a month's salary weep