The time on the job for 17 months would have to be approved via automated underwriting, so that would be the only way to know for sure. Likely it would be OK though. According to my guidelines IndyMac is still OK with 5% down if you can document income... but does require that 680 score, and 9 months PITI in reserves after down payment. Not sure who else permits owner-builder programs other than Bismark, but Bismark requires much more down than IndyMac.
You don't need a web calculator to calculate your DTI, you just take all of your minimum monthly expenses (car payments, credit cards, student loans, personal loans, 401k loans, alimony, child support + the new mortgage payment) and divide it by your total monthly income. The big variable in the equation would be the new mortgage payment, because the only way to figure that out is to know the exact loan amount, interest rate, estimated property taxes/homeowners insurance and PMI (since LTV would be over 80%).
Only way I know of to get a collection off of credit is a pay-for-delete (PFD).
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