Dumb question- is he allowed to do the 4T-3A sequence and the 3A-3S sequence? Would both be considered "3 jump combos"?
No, because 4T+3A+SEQ is a jump sequence with only two jumps and 3A+1Eu+3S is a jump combination with three jumps. Euler counts as a listed jump in this context.
(ETA: I probably should clarify that "jump combination" and "jump sequence" are two different things and the BV is counted differently. In combinations, you simply add up the base values whereas in sequences, the jumps are worth 80% of their BV. So, e.g. 4T+3A+SEQ is worth less than a 3A+4T combo even though those jumping passes contain the same jumps... But it's not like anybody is crazy enough to attempt 3A+4T combos in competition anyway -- at least not yet! -- although some have
tried it in practice)
You physically cannot do an axel as second (or third) jump in your combo because jumps must be landed backwards and the take-off for axel is from the forward edge. I.e. you would have to change foot/edge after landing the first jump for the axel take-off, which means you're not doing a jump combo, you're doing a jump sequence. Doing an euler in-between doesn't help, because that is landed backwards too. So basically, the euler combo thing allows you to change your landing leg & landing edge so you can do a sal or a flip as the 3rd jump in this type of combo, but an axel isn't a possibility.
Or as the tech handbook (pdf available somewhere on the ISU site) says:
In a jump combination the landing foot of a jump is the take off foot of the next jump. One full revolution on the ice between the jumps (free foot can touch the ice, but no weight transfer) keeps the element in the frame of the definition of a jump combination.
An Euler, when used in combinations between two listed jumps, becomes a listed jump (1Eu) with the value indicated in the SOV.
Also, in the new rules, your jump sequence only counts as sequence if the second jump is axel:
A jump sequence consists of 2 (two) jumps of any number of revolutions, beginning with any listed jump, immediately followed by an Axel type jump with a direct step from the landing curve of the first jump to the take-off curve of the Axel jump.
If somebody was to do an intentional 3A+3S+SEQ, I guess it would be judged as a botched attempt at doing a 3A+1Eu+3S combo but without the euler and it would judged as 3A+SEQ+3S* so the 3A would get 80% of BV and salchow would be invalid and receive no value and therefore this jumping pass would only have the BV of 6.4 points, I think? At least I think that's what this means (but my brain is tired so IDK):
If in a jump combination or sequence a skater falls or steps out of a jump and immediately executes another jump(s), the jump(s) after the mistake are not counted, and the call will be the executed jump(s) before the mistake + sequence + the executed jump(s). The jumps after the mistake are marked with an *.
2A(hop)+2A Call: 2A+Seq+2A* 2A+1Eu (fall/step out) +3S Call: 2A+1Eu+Seq+3S*
By doing this all the executed jumps will be visible on the computer screen and it will be easy to follow the requirements of the repetition rule.
The Judges GOE refer to the entire element performed.
The jumps are considered in the order of execution. The point where the mistakeoccurs will be marked with the sign “ + Seq” which results in 80% of the base valuefor the jumps prior to mistake and asterisk (*) for the jumps after it.
E.g.: 3T+2A+Seq.+2T*, 3T+3T+Seq.+2A*, 3T+1Eu+Seq.+2T*
Hope this helps!
I think I fit more into aunt category then. And what was Korea thinking? Giving "adult" men plushies instead of flowers during Olympics 
I need to buy "GOAT" plushie too.
