I will try to answer few questions
Null Rod might be better than Chalice for you. Generally decks that do not want to play Chalice@1 are better off using Null Rod. I would say this is one of those decks. Although Rod shuts off your own Moxen, you can still Weld them out for other stuff.
I tried null rod and finally came back to chalice. The main point is that null rod cost 2. Given that this deck is really not fully powered – cause it doesn’t need it – and that it needs a bazaar online as soon as possible, null rod can often been played only turn 3. And you have to tap all, so stifle cannot be used… That’s mainly the reason why I prefer chalice. I can put it on board freely and keep my mana denial plan with waste or stifle. If moxen are already on board, then shaman and grudges do the job. Then it is also a welder target that can be used turn 2 –when welder is casted turn one.
Another point for chalice is that depending of the situation, I can set it to 1 or 2.
For instance, during some games, I was close to set a lock – crucible and waste – with a welder online, then I set it to 1. Even if it stopped lots of my spells, I was still able to proceed thanks to my lands and thanks to welder. Bazaar helps me to find some cards I can use and discard the ones that are countered by chalice.
Then another point : i tried survival of the fittest in this deck - with a platz in the robot package and a sylvan safekeeper. Survival is extermely syngergistic with the whole deck. I finally cut it cause it is 2CC and so I was generally not able to play it until turn 4 or 5 - not enough mana. That leads me to this conclusion : except if it is an artifact or a "nice discardable card", this deck has lot of difficulties in using efficiently spell which CC is more than 1. Your first turns are always made of "play a land for strip effect, play a bazaar, keep blue open for stifle effect or play a 1CC red creature". After 3 or 4 turns, it is quite common to have only 1 mana available.
Mishra's Factory can really help there. Also Factory allows you to weld in everything over time.
Yes it can and it does

I used to play 1 mishra - in place of 1 wasteland. I am thinking about it right now. How to insert 2 mishra in this deck, so that I got 2 nice blockers -or even finishers.
Since you attack your opponent's manabase, will couples of sphere will be fit in this deck?
This idea was tried but I didn’t make that choice cause stifle and sphere are not working well together. Especially in a deck that has to operate with really few mana – cause of bazaar and waste effects, you don’t often play a real land during your first turns. Then again, it cost 2 (see explanations for null rod)
is the inclusion of green really necessary? The only green card in the deck is Fastbond (and Ancient Grudge). I understand that Fastbond is straight busted, but is it so busted to justify a third color by itself?
That’s a real point. I thought about it a lot : do I need the 3rd color… Right now I am on it but if I succeed in finding useful cards that can be efficiently discarded in red or blue, then I perhaps wouldn’t need green…
What about 1 Sword of Fire and Ice? Monkey/Welder with SOFI for the win?
I like the sofi idea, didn't think about it. Have to try it, it can have its place in this deck
Also, perhaps -1 Titan, +1 Platz in the MD. Platz generally just wins game 1 vs. Ichorid, which is hypothetically the match if you have Leylines in the board.
The robot package can be modified, I think it is really metagame dependant. Used to be 1 sundering and 1 platz. Right now, it is 2 sunderings and 2 platz in side (and 1 more duplicant in side).
Lastly, playing with Gamble in Vintage is so intense it makes me want to kick my mom right in the face.

I love gamble, even if it is sometimes a pain in the ass, it is really often a damn good card.