Be careful you don't compromise any of those tubes, bad things can result.
Wonder what's wrong with the gas ? Usually carbon suggests a slightly off air/fuel ratio. Did you miss a vent tube somewhere ?
Personally, I won't have gas appliances. Seems like every week there's a news story of something burning down or entire homes exploding into splinters.
I know the UK govt had a wild hair up its ass and was intent on switching everyone to electric - UNTIL somebody actually DID THE NUMBERS and they realized they'd have to double or triple the capacity of the national grid ... right down to the level of every little street. That was just an unthinkable expense and SUDDENLY the govt swerved towards other 'fixes'. Now it's "heat pumps", which are fine, but pumps require electricity and typically the "used water" is just dumped out somewhere. LOTS of water.
Oh, they ARE ... by charging 300 to fix a 300 old stove :-)
Anyway, as for PARTS ... older usually meant "simpler" and that puts them in the range of what 3-D printing can now do.
Sounds like a good project. Heating/cooling is always a pain because such systems often use "interesting" wiring and often 24 volts (USA anyhow). Getting the "IQ" down just right will probably take awhile. I'd suggest a good old 'fuzzy logic' approach, esp if you have multiple temperature sensors.
Oh ... and if the wi-fi goes down, can you still make the damned heating work ? "Fail Safe" thinking needs to go into it all. Oh, gas again, if you're using gas heating DO look into CO/CO2 monitors that can shut off the whole thing Just In Case.