Would my wife be eligible for benefits since she is a British citizen?
Child benefit in her name only as it would be a breach of your visa for this to be in your name.
Tax Credits must in in both names as she can't claim to be single when she has a partner because that would be benefit fraud.
Do we have to count my income for it since I have no recourse to public funds?
Yes, Tax Credits are an income based benefit and your income forms part of your joint claim because you are expected to contribute to your child's keep too.
For Child Benefit, it is based on whether one of you earns more than about 50k, when it is then tapered to a cut off point.
Even if you earn too much for Child Benefit and can't increase your pension contributions to reduce your salary to a point where you can get Child Benefit, it is still worth your wife claiming CB as she will get a credit towards her state pension if she isn't returning to work this year. You would then have to pay that money back via a SA each year with HMRC and will be fined if you don't file that SA in time.
Child Tax Credits will be based on your joint income for the tax year April 2015/6. If there is a drop in income this tax year then 2,500 of that drop will be diregarded. i.e. 2015/16 income was 28k and this tax year's is expected to be 20k, then your claim will based on 22.5k.
26k is about the cap for 1 child, with no disabilities and no childcare costs
Any guidance on where to go from here would be appreciated!
Both of those benefits are presently claimed from HMRC.
https://www.gov.uk/child-benefit/overviewhttps://www.gov.uk/child-tax-credithttps://www.gov.uk/government/collections/tax-credits-entitlement-tables